A364135 Let d_r d_{r-1} ... d_1 d_0 be the decimal expansion of n; a(n) is the number of nonnegative integer solutions x_r ... x_0 to the Diophantine equation d_r*x_r + ... + d_0*x_0 = n.
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 12, 7, 5, 4, 4, 3, 3, 3, 3, 1, 11, 12, 4, 7, 3, 5, 2, 4, 2, 1, 11, 6, 12, 3, 3, 7, 2, 2, 5, 1, 11, 11, 4, 12, 3, 4, 2, 7, 2, 1, 11, 6, 4, 3, 12, 2, 2, 2, 2, 1, 11, 11, 11, 6, 3, 12, 2, 3, 4, 1, 11, 6, 4, 3, 3, 2, 12, 2, 2, 1, 11, 11
Offset: 1
Examples
For n = 10: 1*x_1 + 0*x_0 = 10, the solution is x_1 = 10, thus a(10) = 1. For n = 22: 2*x_1 + 2*x_0 = 22, the solutions are (0,11), (2,10), ..., (11,0), thus a(22) = 12.
Links
- Robert P. P. McKone, Table of n, a(n) for n = 1..636
- Eteri Samsonadze, On the number of integer non-negative solutions of a linear Diophantine equation, arXiv:2108.04756 [math.NT], 2021.
Programs
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Mathematica
a[n_Integer] := Module[{ds = IntegerDigits[n], p, t, v}, p = Table[If[d == 0, {0}, Range[0, Quotient[n, d]]], {d, ds}]; t = Tuples[p]; v = Select[t, ds . # == n &]; Length[v]]; Table[a[n], {n, 1, 82}] (* Robert P. P. McKone, Aug 25 2023 *) a[n_]:=Length[IntegerPartitions[n, All,DeleteCases[ IntegerDigits[n],0]]]; Array[a,82] (* Stefano Spezia, Feb 17 2024 *)
Formula
a(n) = 1 for n = (d 0 ... 0), the digit d >= 1, the number of zeros >= 0.
a(n) = (1 ... 1) + 1 for n = (d ... d), the digit d >= 1, n >= 10.
Comments