A291754 a(n) is the length of stage n in A137844.

1, 3, 7, 15, 30, 61, 123, 247, 495, 991, 1983, 3967, 7934, 15869, 31739, 63479, 126959, 253919, 507839, 1015678, 2031357, 4062715, 8125431, 16250863, 32501727, 65003455, 130006911, 260013822, 520027645, 1040055291, 2080110583, 4160221167, 8320442335, 16640884671

Offset

1,2

Links

Paolo Xausa, Table of n, a(n) for n = 1..2000

Formula

a(1) = 1; for n > 1, a(n) = 2*a(n-1) + (A137844(n-1) mod 2).

Mathematica

FoldList[2*# + Mod[#2, 2] &, 1, Fold[Join[#, If[OddQ[#[[#2]]], {#2}, {}], #] &, {1}, Range[5]]] (* Paolo Xausa, Feb 12 2025 *)

Prog

(Scheme) ;; Use the program given in A137844.

Crossrefs

Cf. A137844, A291753.

Sequence in context: A350606 A224520 A373089 * A336685 A069112 A064084

Adjacent sequences: A291751 A291752 A291753 * A291755 A291756 A291757

Keyword

nonn,changed

Author

Antti Karttunen, Aug 31 2017

Status

approved