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.

A093138 Expansion of (1-7x)/(1-10x).

Original entry on oeis.org

1, 3, 30, 300, 3000, 30000, 300000, 3000000, 30000000, 300000000, 3000000000, 30000000000, 300000000000, 3000000000000, 30000000000000, 300000000000000, 3000000000000000, 30000000000000000, 300000000000000000, 3000000000000000000, 30000000000000000000, 300000000000000000000
Offset: 0

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Author

Paul Barry, Mar 24 2004

Keywords

Comments

Partial sums are A093137. A convex combination of 10^n and 0^n.

Crossrefs

Cf. A093137.

Programs

  • PARI
    Vec((1-7*x)/(1-10*x) + O(x^30)) \\ Michel Marcus, Sep 07 2015

Formula

a(n) = 3*10^n/10 + 7*0^n/10.
a(n) = 3*10^(n-1) with a(0)=1. - Vincenzo Librandi, Aug 02 2010
E.g.f.: (3*exp(10*x) + 7)/10. - Elmo R. Oliveira, Aug 13 2024