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.

A278297 a(n) = A278296(n) - A238132(n).

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 4, 6, 10, 14, 22, 28, 40, 52, 70, 88, 116, 142, 180, 228, 280, 342, 422, 510, 620, 750, 902, 1084, 1296, 1544, 1834, 2182, 2574, 3042, 3580, 4208, 4920, 5762, 6728, 7838, 9108, 10574, 12240
Offset: 0

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Author

Vladimir Reshetnikov, Nov 17 2016

Keywords

Crossrefs

Programs

  • Mathematica
    Table[SeriesCoefficient[FunctionExpand[Sum[(2^n - 2 n) x^(n (2 n + 1))/QPochhammer[x, x, 2 n], {n, 0, Sqrt[k/2]}]], {x, 0, k}], {k, 0, 60}]

Formula

G.f.: Sum_{k>=0} (2^n - 2*n) * x^(n*(2*n+1)) / (x; x){2*n}, where (a; q)_n = Product{k=0..n-1} (1 - a*q^n) is the q-Pochhammer symbol.

A278298 Expansion of ((sqrt(2);x)_inf + (-sqrt(2);x)_inf - 2)/4, where(a;q)_inf is the q-Pochhammer symbol.

Original entry on oeis.org

1, 1, 2, 2, 3, 5, 6, 8, 11, 15, 18, 24, 29, 37, 48, 58, 71, 89, 108, 132, 163, 195, 236, 284, 341, 405, 486, 578, 683, 809, 954, 1120, 1319, 1543, 1806, 2112, 2457, 2857, 3320, 3850, 4451, 5149, 5936, 6840, 7879, 9047, 10376, 11900, 13613, 15561, 17770, 20266
Offset: 1

Views

Author

Vladimir Reshetnikov, Nov 17 2016

Keywords

Comments

The q-Pochhammer symbol (a;q)inf = Product{k>=0} (1 - a*q^k).
a(n) agrees with A118399(n) for n < 15.

Crossrefs

Programs

  • Mathematica
    ((QPochhammer[Sqrt[2], x] + QPochhammer[-Sqrt[2], x] - 2)/4 + O[x]^53)[[3]]

Formula

a(n) ~ sqrt(1 + sqrt(2)) * c^(1/4) * exp(2*sqrt(c*n)) / (8*sqrt(Pi)*n^(3/4)), where c = Pi^2/6 + log(2)^2/8 + polylog(2, -1/sqrt(2)) = 1.0944511783086747574574059... - Vaclav Kotesovec, Oct 11 2018
Showing 1-2 of 2 results.