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URL: https://oeis.org/A280655

⇱ A280655 - OEIS

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A280655
Numerator of (Sum_{k=0..n^2-1} (-1)^k*sqrt(Pi)/(Gamma(1/2-k)*Gamma(1+k))) - n.
2
0, 3, 11091, 32104739, 43189424229655, 110209500084824275641, 17401090686295157740521962087, 1341749054684714449837337405947519267, 416437630008271514606815213642830281374740126189, 31880038884855523088456476438831355463732624957105297113285
OFFSET
1,2
COMMENTS
a(n) has at most n prime factors.
FORMULA
a(n)=Numerator of Sum_{k=0..n^2-1}(Binomial(2k,k)/4^k)-n.
MATHEMATICA
Numerator[Table[Sum[Binomial[2k, k]/4^k, {k, 0, n^2-1}]-n, {n, 1, 10}]]
CROSSREFS
Cf. A280656 (denominators), A285388.
Sequence in context: A280300 A375690 A171363 * A262651 A309246 A055379
KEYWORD
nonn,frac
AUTHOR
Ralf Steiner, Apr 12 2017
STATUS
approved