A341206 Number of ways to write n as an ordered sum of 9 nonzero decimal palindromes.

1, 9, 45, 165, 495, 1287, 3003, 6435, 12870, 24301, 43686, 75249, 124809, 200115, 311157, 470415, 693000, 996633, 1401436, 1929465, 2603979, 3448440, 4485267, 5734395, 7211718, 8927523, 10885050, 13079257, 15496065, 18112050, 20894757, 23803659, 26791749, 29807697, 32798448

Offset: 9

Author

Ilya Gutkovskiy, Feb 06 2021

Keywords

• nonn
• base

Links

• Alois P. Heinz, Table of n, a(n) for n = 9..10000

Crossrefs

Cf. A002113, A136522, A319474, A341167, A341184, A341191, A341192, A341193, A341203, A341204, A341205, A341207.

Programs

Maple

p:= proc(n) option remember; local i, s; s:= ""||n;
      for i to iquo(length(s), 2) do if
        s[i]<>s[-i] then return false fi od; true
    end:
b:= proc(n, t) option remember; `if`(n=0, `if`(t=0, 1, 0),
      `if`(t<1, 0, add(`if`(p(j), b(n-j, t-1), 0), j=1..n)))
    end:
a:= n-> b(n, 9):
seq(a(n), n=9..43);  # Alois P. Heinz, Feb 07 2021

Mathematica

nmax = 43; CoefficientList[Series[Sum[Boole[PalindromeQ[k]] x^k, {k, 1, nmax}]^9, {x, 0, nmax}], x] // Drop[#, 9] &