OFFSET
1,3
FORMULA
PROG
(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 n<x+y else prod(map(int, str(n-y)))**2 # Chai Wah Wu, Jun 14 2024
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Giovanni Teofilatto, Jan 02 2006
EXTENSIONS
More terms from Joshua Zucker, May 03 2006
STATUS
approved