A112875 Product of digits of n-th base 10 palindrome.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 1, 4, 9, 16, 25, 36, 49, 64, 81, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 0, 9, 18, 27, 36, 45, 54, 63, 72, 81, 0, 16, 32, 48, 64, 80, 96, 112, 128, 144, 0, 25, 50, 75, 100, 125, 150, 175, 200, 225, 0, 36, 72, 108, 144, 180, 216

Offset: 1

Author

Giovanni Teofilatto, Jan 02 2006

Keywords

• base
• easy
• nonn

Crossrefs

Cf. A002113, A007954.

Programs

Python

from math import prod
def A112875(n):
    if n == 1: return 0
    y = 10*(x:=10**(len(str(n>>1))-1))
    return int((s:=str(n-x))[-1])*prod(int(d) for d in s[:-1])**2 if nChai Wah Wu, Jun 14 2024

Formula

a(n) = A007954(A002113(n)). - Michel Marcus, Jun 14 2024~

Extensions

More terms from Joshua Zucker, May 03 2006