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A050025 a(n) = a(n-1) + a(m) for n >= 4, where m = 2^(p+1) + 2 - n and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = a(2) = a(3) = 1. 12
1, 1, 1, 2, 3, 5, 6, 7, 8, 15, 21, 26, 29, 31, 32, 33, 34, 67, 99, 130, 159, 185, 206, 221, 229, 236, 242, 247, 250, 252, 253, 254, 255, 509, 762, 1014, 1264, 1511, 1753, 1989, 2218, 2439, 2645, 2830, 2989, 3119, 3218, 3285, 3319 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Ivan Neretin, Table of n, a(n) for n = 1..8193

MAPLE

a := proc(n) option remember;

`if`(n < 4, 1, a(n - 1) + a(Bits:-Iff(n - 2, n - 2) + 3 - n)); end proc;

seq(a(n), n = 1 .. 48); # Petros Hadjicostas, Nov 08 2019

MATHEMATICA

Fold[Append[#1, #1[[-1]] + #1[[#2]]] &, {1, 1, 1}, Flatten@Table[k, {n, 5}, {k, 2^n, 1, -1}]] (* Ivan Neretin, Sep 06 2015 *)

PROG

(PARI) lista(nn) = {nn = max(nn, 3); my(va = vector(nn)); va[1] = 1; va[2] = 1; va[3] = 1; for(n=4, nn, va[n] = va[n-1] + va[2*2^logint(n-2, 2) + 2 - n]); va; } \\ Petros Hadjicostas, May 03 2020

CROSSREFS

Sequence in context: A197433 A153781 A255398 * A255430 A074492 A059307

Adjacent sequences:  A050022 A050023 A050024 * A050026 A050027 A050028

KEYWORD

nonn

AUTHOR

Clark Kimberling

EXTENSIONS

Name edited by Petros Hadjicostas, Nov 08 2019

STATUS

approved

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Last modified September 24 14:46 EDT 2021. Contains 347643 sequences. (Running on oeis4.)