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.

Previous Showing 11-11 of 11 results.

A302556 Expansion of x*(1 + 2*x*(5 - 4*x)*(1 + x^2)*(1 + x^4))/((1 - x)*(1 - 10*x^9)).

Original entry on oeis.org

0, 1, 11, 3, 13, 5, 15, 7, 17, 9, 19, 119, 39, 139, 59, 159, 79, 179, 99, 199, 1199, 399, 1399, 599, 1599, 799, 1799, 999, 1999, 11999, 3999, 13999, 5999, 15999, 7999, 17999, 9999, 19999, 119999, 39999, 139999, 59999, 159999, 79999, 179999, 99999, 199999, 1199999, 399999
Offset: 0

Views

Author

Ilya Gutkovskiy, Aug 15 2018

Keywords

Comments

a(n) is the smallest number whose sum of odd decimal digits is n.

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[x (1 + 2 x (5 - 4 x) (1 + x^2) (1 + x^4))/((1 - x) (1 - 10 x^9)), {x, 0, 48}], x]
    LinearRecurrence[{1, 0, 0, 0, 0, 0, 0, 0, 10, -10}, {0, 1, 11, 3, 13, 5, 15, 7, 17, 9}, 49]

Formula

G.f.: x*(1 + 2*x*(5 - 4*x)*(1 + x^2)*(1 + x^4))/((1 - x)*(1 - 10*x^9)).
a(n) = a(n-1) + 10*a(n-9) - 10*a(n-10).
Previous Showing 11-11 of 11 results.