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A049891 a(n) = a(1) + a(2) + ... + 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) = a(2) = 1 and a(3) = 2. 3
1, 1, 2, 3, 4, 10, 18, 29, 39, 106, 210, 413, 807, 1537, 2767, 4410, 5947, 16303, 32604, 65201, 130383, 260689, 521071, 1041018, 2079163, 4146433, 8243968, 16292448, 31804567, 60503719, 108861423, 173511575, 234015294, 641542162 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..34.

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[2*(n - 1 - 2^logint(n-2, 2))]; sa += va[n]; ); va; } \\ Petros Hadjicostas, May 03 2020

CROSSREFS

Cf. A049890 (similar with minus a(m/2)), A049938 (similar with plus a(m/2)), A049939 (similar with plus a(m)).

Sequence in context: A098088 A080500 A007661 * A135432 A108364 A346489

Adjacent sequences:  A049888 A049889 A049890 * A049892 A049893 A049894

KEYWORD

nonn

AUTHOR

Clark Kimberling

EXTENSIONS

Name edited by Petros Hadjicostas, May 03 2020

STATUS

approved

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Last modified October 17 15:18 EDT 2021. Contains 348049 sequences. (Running on oeis4.)