A049910 - OEIS

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A049910

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) = 2, and a(3) = 3.

1, 2, 3, 5, 9, 19, 37, 73, 144, 292, 583, 1165, 2328, 4652, 9294, 18570, 37104, 74280, 148559, 297117, 594232, 1188460, 2376910, 4753802, 9507568, 19015065, 38029982, 76059673, 152118764, 304236365, 608470406, 1216936170, 2433863064

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Table of n, a(n) for n=1..33.

PROG

(PARI) lista(nn) = { my(va = vector(nn)); va[1] = 1; va[2] = 2; va[3] = 3; my(sa = vecsum(va)); for (n=4, nn, va[n] = sa - va[n - 1 - 2^ceil(-1 + log(n-1)/log(2))]; sa += va[n]; ); va; } \\ Petros Hadjicostas, Apr 26 2020 (with nn > 2)

CROSSREFS

Cf. A049911 (similar, but with minus a(2*m)), A049958 (similar, but with plus a(m)), A049959 (similar, but with plus a(2*m)).

Sequence in context: A003218 A119002 A058770 * A077643 A123389 A113984

Adjacent sequences: A049907 A049908 A049909 * A049911 A049912 A049913

KEYWORD

nonn

AUTHOR

Clark Kimberling

EXTENSIONS

Name edited by Petros Hadjicostas, Apr 26 2020

STATUS

approved