A050047 a(n) = a(n-1) + a(m) for n >= 4, where m = 2*n - 2 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1 and a(2) = a(3) = 2.

1, 2, 2, 4, 8, 10, 14, 24, 48, 50, 54, 64, 88, 138, 202, 340, 680, 682, 686, 696, 720, 770, 834, 972, 1312, 1994, 2690, 3460, 4432, 6426, 9886, 16312, 32624, 32626, 32630, 32640, 32664, 32714, 32778, 32916, 33256, 33938, 34634

Offset

1,2

Links

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

Mathematica

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

Prog

(PARI) lista(nn) = {nn = max(nn, 3); my(va = vector(nn)); va[1] = 1; va[2] = 2; va[3] = 2; for(n=4, nn, va[n] = va[n-1] + va[2*(n - 1 - 2^logint(n-2, 2))]); va; } \\ Petros Hadjicostas, Jul 19 2020

Crossrefs

Cf. A050027, A050031, A050035, A050039, A050043, A050051, A050055, A050059, A050063, A050067, A050071 (similar, but with different initial conditions).

Sequence in context: A085620 A325867 A333045 * A056381 A245597 A324039

Adjacent sequences: A050044 A050045 A050046 * A050048 A050049 A050050

Keyword

nonn

Author

Clark Kimberling

Extensions

Name edited by Petros Hadjicostas, Jul 19 2020

Status

approved