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.

Previous Showing 21-24 of 24 results.

A009200 E.g.f. exp(sin(log(1+x))).

Original entry on oeis.org

1, 1, 0, -1, 2, -4, 16, -120, 1084, -10568, 111196, -1269764, 15728360, -210510936, 3029497472, -46654106824, 765497451536, -13330741903360, 245546485746064, -4769321293582128, 97417091239222336, -2087367002843576384, 46814167766826521920, -1096698328458955351616
Offset: 0

Views

Author

Keywords

Crossrefs

Cf. A002017.

Programs

  • PARI
    x='x+O('x^30); Vec(serlaplace(exp(sin(log(1+x))))) \\ Michel Marcus, Apr 01 2017

Formula

a(n) = Sum_{k=1..n} stirling1(n,k)*A002017(k), n > 0, a(0)=1. - Vladimir Kruchinin, Jun 29 2011

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

A009206 Expansion of e.g.f.: exp(sin(x))*x.

Original entry on oeis.org

0, 1, 2, 3, 0, -15, -48, -21, 448, 1953, 640, -32461, -152064, 77649, 4331264, 18557595, -46686208, -894805183, -2948087808, 21405607651, 254321049600, 421226202033, -10904188190720, -90171090228021, 96102216892416, 6418365899545825
Offset: 0

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Author

Keywords

Programs

  • Mathematica
    With[{nn=30},CoefficientList[Series[Exp[Sin[x]]*x,{x,0,nn}],x] Range[ 0,nn]!] (* Harvey P. Dale, Dec 25 2021 *)

Formula

a(n) = n * A002017(n-1). - Ralf Stephan, Sep 01 2003
E.g.f.: x*E(0) -x, where E(k) = 2 + sin(x)/(2*k+1 - sin(x)/E(k+1) ); (continued fraction). - Sergei N. Gladkovskii, Dec 24 2013

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997
Definition clarified and prior Mathematica program replaced by Harvey P. Dale, Dec 25 2021

A293021 a(n) = n! * [x^n] exp(n*sin(x)).

Original entry on oeis.org

1, 1, 4, 24, 192, 1880, 21312, 266504, 3469312, 42094656, 297625600, -8727514752, -659406274560, -31019532622208, -1314656227540992, -54314985911216640, -2248955319931633664, -94369141109824233472, -4028982346754921594880, -175032005028072692797440
Offset: 0

Views

Author

Ilya Gutkovskiy, Sep 28 2017

Keywords

Crossrefs

Cf. A002017.

Programs

  • Mathematica
    Table[n! SeriesCoefficient[Exp[n Sin[x]], {x, 0, n}], {n, 0, 19}]

A381343 Expansion of e.g.f. exp( sin(sqrt(2)*x) / sqrt(2) ).

Original entry on oeis.org

1, 1, 1, -1, -7, -15, 25, 287, 721, -2847, -30255, -61697, 682761, 5861713, 3105193, -258188513, -1681060063, 4623681473, 135471132705, 564325398271, -6357495670375, -89817656595791, -84337394884167, 7820620314702879, 67277670159083761, -322108989883888479
Offset: 0

Views

Author

Seiichi Manyama, Feb 20 2025

Keywords

Crossrefs

Programs

  • PARI
    a136630(n, k) = 1/(2^k*k!)*sum(j=0, k, (-1)^(k-j)*(2*j-k)^n*binomial(k, j));
    a(n) = sum(k=0, n, (-2)^((n-k)/2)*a136630(n, k));

Formula

a(0) = 1; a(n) = Sum_{k=0..floor((n-1)/2)} (-2)^k * binomial(n-1,2*k) * a(n-2*k-1).
a(n) = Sum_{k=0..n} (-2)^((n-k)/2) * A136630(n,k).
Previous Showing 21-24 of 24 results.