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.

A133899 Numbers m such that binomial(m+9,m) mod 9 = 0.

Original entry on oeis.org

72, 73, 74, 75, 76, 77, 78, 79, 80, 153, 154, 155, 156, 157, 158, 159, 160, 161, 234, 235, 236, 237, 238, 239, 240, 241, 242, 315, 316, 317, 318, 319, 320, 321, 322, 323, 396, 397, 398, 399, 400, 401, 402, 403, 404, 477, 478, 479, 480, 481, 482, 483, 484, 485
Offset: 0

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Author

Hieronymus Fischer, Oct 20 2007

Keywords

Comments

Also numbers m such that floor(1+(m/9)) mod 9 = 0.
Partial sums of the sequence 72,1,1,1,1,1,1,1,1,73,1,1,1,1,1,1,1,1,73, ... which has period 9.

Crossrefs

Programs

  • Mathematica
    Select[Range[500],Divisible[Binomial[#+9,#],9]&] (* Harvey P. Dale, Apr 03 2011 *)

Formula

a(n)=9n+72-8*(n mod 9).
G.f.: g(x)=(72+x+x^2+x^3+x^4+x^5+x^6+x^7+x^8+x^9)/((1-x^9)(1-x)).
G.f.: g(x)=(72-71x-x^10) /((1-x^9)(1-x)^2).