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A239795 A239793(n)/2^(3*n). 1
1, 3, 5, 21, 45, 11, 91, 45, 17, 1995, 3465, 115, 2925, 189, 145, 341, 1309, 1, 9139, 65, 2255, 148995, 108675, 1645, 270725, 21879, 583, 4389, 4959, 59, 1548729, 27027, 60775, 130985, 15525, 1065, 66047553, 2567565, 39, 2133, 56457, 1411, 8161615, 2639 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

See A239792 for references.

LINKS

Table of n, a(n) for n=0..43.

FORMULA

Let b(n) = -sum_{2<=k<=n}(C(n-1, k-1)*Bernoulli(k)*b(n-k)/k)/2

for n>0 and otherwise 1. Then a(n) = denominator(b(2*n))/2^(3*n).

MAPLE

b := proc(n) option remember; if n < 1 then 1 else

-add(binomial(n-1, k-1)*bernoulli(k)*b(n-k)/k, k= 2..n)/2 fi end:

A239795 := n -> denom(b(2*n))/2^(3*n):

seq(A239795(n), n=0..43);

CROSSREFS

Cf. A220412.

Sequence in context: A148551 A148552 A148553 * A261272 A319488 A110026

Adjacent sequences:  A239792 A239793 A239794 * A239796 A239797 A239798

KEYWORD

nonn

AUTHOR

Peter Luschny, Mar 26 2014

STATUS

approved

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Last modified April 3 19:43 EDT 2020. Contains 333198 sequences. (Running on oeis4.)