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A049890 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) = a(2) = 1 and a(3) = 2. 3
1, 1, 2, 3, 6, 12, 24, 47, 93, 188, 376, 751, 1501, 2999, 5992, 11972, 23921, 47888, 95776, 191551, 383101, 766199, 1532392, 3064772, 6129521, 12258996, 24517897, 49035606, 98070837, 196140924, 392280350, 784557707, 1569109434 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

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

PROG

(PARI) lista(nn) = { nn = max(nn, 3); my(va = vector(nn)); va[1] = 1; va[2] = 1; va[3] = 2; 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, Apr 27 2020

CROSSREFS

Cf. A049891 (similar with minus a(2*m)), A049938 (similar with plus a(m)), A049939 (similar with plus a(2*m)).

Sequence in context: A321048 A038085 A124313 * A262236 A246878 A251709

Adjacent sequences:  A049887 A049888 A049889 * A049891 A049892 A049893

KEYWORD

nonn

AUTHOR

Clark Kimberling

EXTENSIONS

Name edited by Petros Hadjicostas, Apr 27 2020

STATUS

approved

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Last modified November 28 08:12 EST 2021. Contains 349401 sequences. (Running on oeis4.)