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.

A293586 Number of compositions of n where each part i is marked with a word of length i over a nonary alphabet whose letters appear in alphabetical order and all nine letters occur at least once in the composition.

Original entry on oeis.org

7087261, 492006708, 19423259316, 574637640288, 14193955791576, 309660911167464, 6171397007611848, 114853532449557600, 2026594842428425320, 34277110454602760762, 560261324259420037164, 8904738970375872782112, 138290600270036591006520, 2106511986693346884064584
Offset: 9

Views

Author

Alois P. Heinz, Oct 12 2017

Keywords

Crossrefs

Column k=9 of A261781.

Programs

  • Maple
    b:= proc(n, k) option remember; `if`(n=0, 1,
          add(b(n-j, k)*binomial(j+k-1, k-1), j=1..n))
        end:
    a:= n-> (k->add(b(n, k-i)*(-1)^i*binomial(k, i), i=0..k))(9):
    seq(a(n), n=9..30);

Formula

a(n) = 90*a(n-1) - 3720*a(n-2) + 94140*a(n-3) - 1642368*a(n-4) + 21111972*a(n-5) - 208936444*a(n-6) + 1643906838*a(n-7) - 10544413816*a(n-8) + 56273496182*a(n-9) - 254124223400*a(n - 10) + 984813733064*a(n - 11) - 3313818868728*a(n - 12) + 9777617820932*a(n - 13) - 25505157099056*a(n - 14) + 59222241227144*a(n - 15) - 123105458091224*a(n - 16) + 230174411303404*a(n - 17) - 388610578141384*a(n - 18) + 594331344450528*a(n - 19) - 825476563250976*a(n - 20) + 1043293124084592*a(n - 21) - 1201650502768408*a(n - 22) + 1262594519234968*a(n - 23) - 1210928179506120*a(n - 24) + 1060266691901408*a(n - 25) - 847323181595664*a(n - 26) + 617639581793392*a(n - 27) - 410205458302944*a(n - 28) + 247843724510640*a(n - 29) - 135949707500048*a(n - 30) + 67526545242016*a(n - 31) - 30273460576096*a(n - 32) + 12201462236512*a(n - 33) - 4399521714368*a(n - 34) + 1410734015840*a(n - 35) - 399326676032*a(n - 36) + 98870585152*a(n - 37) - 21165129088*a(n - 38) + 3859085248*a(n - 39) - 587513600*a(n - 40) + 72658304*a(n - 41) - 7011968*a(n - 42) + 495360*a(n - 43) - 22784*a(n - 44) + 512*a(n - 45). - Vaclav Kotesovec, Oct 14 2017