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.

A119383 a(n) = n!- A088921(n).

Original entry on oeis.org

0, 0, 0, 1, 11, 87, 640, 4855, 39909, 361995, 3626938, 39912947, 478993719, 6227004807, 87178258916, 1307674303055, 20922789757641, 355687427834707, 6402373705204718, 121645100407784603, 2432902008174544219
Offset: 0

Views

Author

Roger L. Bagula, Jun 07 2007

Keywords

Crossrefs

Cf. A088921.

Programs

  • Mathematica
    g[n_] = n! - (2^(n + 1) - Binomial[n + 1, 3] - 2*n - 1); Table[g[n], {n, 0, 30}]

Extensions

Offset set to 0, definition shortened, References converted to URL's - The Assoc. Eds. of the OEIS, Oct 20 2010

A179257 Number of permutations of length n which avoid the patterns 321 and 1324.

Original entry on oeis.org

1, 1, 2, 5, 13, 32, 72, 148, 281, 499, 838, 1343, 2069, 3082, 4460, 6294, 8689, 11765, 15658, 20521, 26525, 33860, 42736, 53384, 66057, 81031, 98606, 119107, 142885, 170318, 201812, 237802, 278753, 325161, 377554, 436493, 502573, 576424, 658712, 750140, 851449
Offset: 0

Views

Author

Vincent Vatter, Jul 05 2010

Keywords

Examples

			There are 13 permutations of length 4 which avoid these two patterns, so a(4)=13.
		

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{6,-15,20,-15,6,-1},{1,1,2,5,13,32},50] (* Harvey P. Dale, May 19 2024 *)

Formula

a(n) = 1+binomial(n,2)+binomial(n+2,5).
G.f.: 1-x*(x^5-4*x^4+7*x^3-8*x^2+4*x-1)/(x-1)^6. - Colin Barker, Aug 02 2012
a(n) = 1+A027658(n-2). - R. J. Mathar, Aug 19 2022

Extensions

a(0)=1 prepended by Alois P. Heinz, Jul 05 2018
Showing 1-2 of 2 results.