A275531 Values taken by the sum of numbers in Collatz trajectory (A033493), sorted into ascending order.

1, 3, 7, 15, 31, 36, 46, 49, 55, 63, 66, 67, 91, 106, 119, 127, 139, 145, 148, 186, 190, 197, 214, 235, 248, 255, 259, 274, 281, 288, 301, 302, 316, 325, 330, 339, 346, 357, 386, 393, 399, 413, 427, 442, 442, 452, 465, 497, 498, 500, 505, 509, 511, 519, 535, 540

Offset: 1

Author

Jaroslav Krizek, Jul 31 2016

Keywords

• nonn

Comments

Values a(n) such that a(n) = a(n+1): 442, 609, 633, 724, 904, 925, ...

Links

• Eric Weisstein's World of Mathematics, Collatz Problem
• Wikipedia, Collatz conjecture

Crossrefs

Cf. A033493, A275532.

Programs

Magma

Sort([&+[k eq 1 select n else IsOdd(Self(k-1)) and not IsOne(Self(k-1)) select 3*Self(k-1)+1 else Self(k-1) div 2: k in [1..5*n]]: n in [1..2^10] | &+[k eq 1 select n else IsOdd(Self(k-1)) and not IsOne(Self(k-1)) select 3*Self(k-1)+1 else Self(k-1) div 2: k in [1..5*n]] le 2^10])