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.

A259969 a(n) = n*A259968(n).

Original entry on oeis.org

0, 1, 2, 9, 24, 50, 102, 210, 424, 837, 1630, 3146, 6024, 11453, 21644, 40695, 76176, 142035, 263916, 488870, 903060, 1663998, 3059166, 5612483, 10277448, 18787150, 34287916, 62485371, 113715448, 206683725, 375211710, 680399005, 1232533696, 2230537914
Offset: 0

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Author

N. J. A. Sloane, Jul 11 2015

Keywords

References

  • R. K. Guy, Letter to N. J. A. Sloane, Feb 05 1986.

Crossrefs

Programs

  • Haskell
    a259967 n = a259967_list !! n
    a259967_list = 3 : 2 : 2 : 5 : zipWith3 (((+) .) . (+))
       a259967_list (drop 2 a259967_list) (drop 3 a259967_list)
    -- Reinhard Zumkeller, Jul 12 2015
  • PARI
    concat(0, Vec(x*(x^4-6*x^3+7*x^2-2*x+1)/(x^3-x^2+2*x-1)^2 + O(x^40))) \\ Colin Barker, Jul 12 2015
    

Formula

G.f.: x*(x^4-6*x^3+7*x^2-2*x+1) / (x^3-x^2+2*x-1)^2. - Colin Barker, Jul 12 2015

Extensions

a(28)-a(33) from Hiroaki Yamanouchi, Jul 12 2015