A275532 Possible values for 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, 452, 465, 497, 498, 500, 505, 509, 511, 519, 535, 540, 557

Offset

1,2

Comments

Values a(n) such that a(n) = A033493(x) = A033493(y) for distinct numbers x and y: 442, 609, 633, 724, 904, 925, ...

Links

Table of n, a(n) for n=1..56.

Mathematica

Take[#, 56] &@ Union@ Table[Total@ FixedPointList[Which[# == 1, 1, OddQ@ #, 3 # + 1, True, #/2] &, n] - 1, {n, 10^3}] (* Michael De Vlieger, Aug 02 2016 *)

Prog

(Magma) Set(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]))

Crossrefs

Cf. A033493, A275531.

Sequence in context: A320024 A098583 A275531 * A212315 A043729 A331503

Adjacent sequences: A275529 A275530 A275531 * A275533 A275534 A275535

Keyword

nonn

Author

Jaroslav Krizek, Jul 31 2016

Status

approved