OFFSET
1,11
COMMENTS
For a formula for a(n), please see the Samsonadze article in Links section. a(n) = P(b) if n = b AND the nonzero digits of b are the coefficients a_i (in the article).
a(n) is the number of partitions of n into parts that are nonzero digits of n. - Stefano Spezia, Feb 17 2024
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.
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.
EXAMPLE
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.
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 *)
CROSSREFS
KEYWORD
AUTHOR
Ctibor O. Zizka, Jul 10 2023
STATUS
approved