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A370679
a(n) is the number of pairs x <= y of n-digit numbers such that the number of distinct digits in their product is the same as in their concatenation.
5
29, 1674, 136854, 12082393, 1136370471, 111392993465
OFFSET
1,1
PROG
(PARI) See A370678.
(Python)
def A370679(n):
a = 10**(n-1)
b, c = 10*a, 0
for x in range(a, b):
s = set(str(x))
for y in range(x, b):
if len(s|set(str(y))) == len(set(str(x*y))):
c += 1
return c # Chai Wah Wu, Feb 28 2024
CROSSREFS
KEYWORD
nonn,base,more
AUTHOR
Hugo Pfoertner, Feb 26 2024
EXTENSIONS
a(6) from Martin Ehrenstein, Feb 29 2024
STATUS
approved