A211072 Sum of numbers with no '0' decimal digits whose sum of digits equals n.
0, 1, 13, 147, 1625, 17891, 196833, 2165227, 23817625, 261994131, 2881935943, 31701296375, 348714262017, 3835856884757, 42194425724149, 464138682802857, 5105525508895321, 56160780576260645, 617768586100819485, 6795454444489330049, 74749998860563784655
Offset: 0
Examples
2 and 11 are the only numbers without 0's which have digit sum 2, so a(2) = 2 + 11 = 13.
Links
- Alois P. Heinz, Table of n, a(n) for n = 0..961 (terms n = 1..31 from Laurent Desnogues)
- Project Euler, Problem 377: Sum of digits, experience 13
- Tadao Takaoku, A two-level algorithm for generating multiset permutations, RIMS Kokyuroku 1644 (2009), pp. 95-109.
- Index entries for linear recurrences with constant coefficients, signature (11,1,-9,-19,-29,-39,-49,-59,-69,-90,-80,-70,-60,-50,-40,-30,-20,-10).
Programs
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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
Comments