A049966 - OEIS

A049966

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

1, 3, 1, 6, 14, 26, 54, 106, 217, 429, 860, 1718, 3441, 6890, 13792, 27612, 55276, 110447, 220896, 441790, 883585, 1767178, 3534368, 7068764, 14137580, 28275271, 56550754, 113101939, 226204736, 452411195, 904825839, 1809658580

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..32.

PROG

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

CROSSREFS

Cf. A049918 (similar, but with minus a(m)), A049919 (similar, but with minus a(2*m)), A049967 (similar, but with plus a(2*m)).

Sequence in context: A143984 A051124 A193091 * A187120 A350610 A140982

Adjacent sequences: A049963 A049964 A049965 * A049967 A049968 A049969

KEYWORD

nonn

AUTHOR

Clark Kimberling

EXTENSIONS

Name edited by Petros Hadjicostas, Apr 24 2020

STATUS

approved