cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-2 of 2 results.

A281264 Base-2 logarithm of denominator of (Sum_{k=0..n^2-1} (-1)^k*sqrt(Pi)/(Gamma(1/2-k)*Gamma(1+k))) - n.

Original entry on oeis.org

0, 4, 15, 26, 46, 67, 94, 120, 158, 194, 236, 281, 333, 386, 445, 502, 574, 642, 716, 792, 875, 960, 1054, 1143, 1244, 1345, 1451, 1560, 1676, 1793, 1916, 2036, 2174, 2306, 2444, 2584, 2731, 2880, 3034, 3190, 3356, 3519, 3690, 3862, 4041, 4226, 4413, 4597, 4796, 4992
Offset: 1

Views

Author

Ralf Steiner, Apr 13 2017

Keywords

Crossrefs

Cf. A280656, A007814.

Programs

  • Mathematica
    f[n_] := Log2[ Denominator[ Sum[ Binomial[2m, m]/4^m, {m, 0, n^2 -1}] -n]]; Array[f, 50]

A280655 Numerator of (Sum_{k=0..n^2-1} (-1)^k*sqrt(Pi)/(Gamma(1/2-k)*Gamma(1+k))) - n.

Original entry on oeis.org

0, 3, 11091, 32104739, 43189424229655, 110209500084824275641, 17401090686295157740521962087, 1341749054684714449837337405947519267, 416437630008271514606815213642830281374740126189, 31880038884855523088456476438831355463732624957105297113285
Offset: 1

Views

Author

Ralf Steiner, Apr 12 2017

Keywords

Comments

a(n) has at most n prime factors.

Crossrefs

Cf. A280656 (denominators), A285388.

Programs

  • Mathematica
    Numerator[Table[Sum[Binomial[2k,k]/4^k,{k,0,n^2-1}]-n,{n,1,10}]]

Formula

a(n)=Numerator of Sum_{k=0..n^2-1}(Binomial(2k,k)/4^k)-n.
Showing 1-2 of 2 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement.