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.

A211072 Sum of numbers with no '0' decimal digits whose sum of digits equals n.

Original entry on oeis.org

0, 1, 13, 147, 1625, 17891, 196833, 2165227, 23817625, 261994131, 2881935943, 31701296375, 348714262017, 3835856884757, 42194425724149, 464138682802857, 5105525508895321, 56160780576260645, 617768586100819485, 6795454444489330049, 74749998860563784655
Offset: 0

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Comments

Different from A016135.

Examples

			2 and 11 are the only numbers without 0's which have digit sum 2, so a(2) = 2 + 11 = 13.
		

Crossrefs

Programs

  • Maple
    b:= proc(n) option remember; `if`(n=0, [1, 0], add((p->
          [p[1], p[2]*10+p[1]*d])(b(n-d)), d=1..min(n, 9)))
        end:
    a:= n-> b(n)[2]:
    seq(a(n), n=0..23);  # Alois P. Heinz, Feb 19 2020

Formula

G.f.: x*(9*x^8 + 8*x^7 + 7*x^6 + 6*x^5 + 5*x^4 + 4*x^3 + 3*x^2 + 2*x + 1)/((x^9 + x^8 + x^7 + x^6 + x^5 + x^4 + x^3 + x^2 + x - 1)*(10*x^9 + 10*x^8 + 10*x^7 + 10*x^6 + 10*x^5 + 10*x^4 + 10*x^3 + 10*x^2 + 10*x - 1)). - Yurii Ivanov, Jul 06 2021

Extensions

a(0)=0 prepended by Alois P. Heinz, Feb 19 2020