OFFSET
1,1
EXAMPLE
a(1) = 6: 6 squares 4*4, ..., 9*9 with 2 distinct digits in x*y = 16, 25, ..., and 1 digit in their concatenation.
PROG
(PARI) See A370678.
(Python)
def A370680(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