Get the longest Chain under 1 Million.
This problem is from projecteuler.net
The following iterative sequence is defined for the set of positive integers:
n → n/2 (n is even)
n → 3n + 1 (n is odd)
Using the rule above and starting with 13, we generate the following sequence: 13 → 40 → 20 → 10 → 5 → 16 → 8 → 4 → 2 → 1
It can be seen that this sequence (starting at 13 and finishing at 1) contains 10 terms. Although it has not been proved yet (Collatz Problem), it is thought that all starting numbers finish at 1.
Which starting number, under one million, produces the longest chain?
NOTE: Once the chain starts the terms are allowed to go above one million.
Found new record 1: 1 after 0,000s ime since start 0,000s
Found new record 2: 2 after 0,000s ime since start 0,046s
Found new record 3: 8 after 0,000s ime since start 0,048s
Found new record 6: 9 after 0,000s ime since start 0,049s
Found new record 7: 17 after 0,000s ime since start 0,049s
Found new record 9: 20 after 0,000s ime since start 0,050s
Found new record 18: 21 after 0,001s ime since start 0,051s
Found new record 25: 24 after 0,000s ime since start 0,052s
Found new record 27: 112 after 0,000s ime since start 0,053s
Found new record 54: 113 after 0,002s ime since start 0,055s
Found new record 73: 116 after 0,001s ime since start 0,056s
Found new record 97: 119 after 0,000s ime since start 0,057s
Found new record 129: 122 after 0,001s ime since start 0,059s
Found new record 171: 125 after 0,001s ime since start 0,061s
Found new record 231: 128 after 0,001s ime since start 0,063s
Found new record 313: 131 after 0,003s ime since start 0,067s
Found new record 327: 144 after 0,001s ime since start 0,068s
Found new record 649: 145 after 0,008s ime since start 0,076s
Found new record 703: 171 after 0,001s ime since start 0,077s
Found new record 871: 179 after 0,004s ime since start 0,082s
Found new record 1161: 182 after 0,006s ime since start 0,089s
Found new record 2223: 183 after 0,015s ime since start 0,104s
Found new record 2463: 209 after 0,003s ime since start 0,108s
Found new record 2919: 217 after 0,010s ime since start 0,118s
Found new record 3711: 238 after 0,009s ime since start 0,127s
Found new record 6171: 262 after 0,033s ime since start 0,161s
Found new record 10971: 268 after 0,074s ime since start 0,235s
Found new record 13255: 276 after 0,015s ime since start 0,251s
Found new record 17647: 279 after 0,043s ime since start 0,295s
Found new record 23529: 282 after 0,071s ime since start 0,366s
Found new record 26623: 308 after 0,029s ime since start 0,395s
Found new record 34239: 311 after 0,056s ime since start 0,451s
Found new record 35655: 324 after 0,011s ime since start 0,462s
Found new record 52527: 340 after 0,168s ime since start 0,630s
Found new record 77031: 351 after 0,222s ime since start 0,852s
Found new record 106239: 354 after 0,306s ime since start 1,158s
Found new record 142587: 375 after 0,367s ime since start 1,525s
Found new record 156159: 383 after 0,110s ime since start 1,635s
Found new record 216367: 386 after 0,566s ime since start 2,202s
Found new record 230631: 443 after 0,147s ime since start 2,349s
Found new record 410011: 449 after 1,808s ime since start 4,158s
Found new record 511935: 470 after 1,028s ime since start 5,186s
Found new record 626331: 509 after 1,224s ime since start 6,410s
Found new record 837799: 525 after 2,208s ime since start 8,619s
Found new record 1117065: 528 after 3,251s ime since start 11,870s
Found new record 1501353: 531 after 4,430s ime since start 16,300s
Found new record 1723519: 557 after 2,487s ime since start 18,787s
Found new record 2298025: 560 after 6,646s ime since start 25,433s
Found new record 3064033: 563 after 8,496s ime since start 33,929s
Found new record 3542887: 584 after 5,827s ime since start 39,757s
Found new record 3732423: 597 after 2,099s ime since start 41,856s