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 A347748 Number of positive integers with n digits that are equal both to the product of two integers ending with 4 and to that of two integers ending with 6. 2
 0, 1, 12, 159, 1859, 20704, 223525, 2370684, 24842265, 258128126 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS a(n) is the number of n-digit numbers in A347746. LINKS FORMULA a(n) < A052268(n). a(n) = A337856(n) + A347255(n) - A347749(n). Conjecture: lim_{n->infinity} a(n)/a(n-1) = 10. MATHEMATICA Table[{lo, hi}={10^(n-1), 10^n}; Length@Select[Intersection[Union@Flatten@Table[a*b, {a, 4, Floor[hi/4], 10}, {b, a, Floor[hi/a], 10}], Union@Flatten@Table[a*b, {a, 6, Floor[hi/6], 10}, {b, a, Floor[hi/a], 10}]], lo<#

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Last modified December 6 06:14 EST 2021. Contains 349563 sequences. (Running on oeis4.)