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A198487
Smallest nonprime positive numbers whose digital product = n, or 0 if impossible.
4
10, 1, 12, 1113, 4, 15, 6, 117, 8, 9, 25, 0, 26, 0, 27, 35, 28, 0, 36, 0, 45, 371, 0, 0, 38, 55, 0, 39, 74, 0, 56, 0, 48, 0, 0, 57, 49, 0, 0, 0, 58, 0, 76, 0, 0, 95, 0, 0, 68, 77, 255, 0, 0, 0, 69, 0, 78, 0, 0, 0, 256, 0, 0, 791, 88, 0, 0, 0, 0, 0, 275, 0, 98, 0, 0, 355
OFFSET
0,1
COMMENTS
Zeros appear for n which are a member of A068191.
If the requirement "positive" is dropped, a(0) becomes 0 instead.
EXAMPLE
a(21)=371 because 371 is the smallest nonprime positive number whose digital product is 21 (3*7*1 = 21).
CROSSREFS
Cf. A107698 (smallest primes with digital product n)
Sequence in context: A332803 A073731 A179937 * A099613 A209924 A209926
KEYWORD
nonn,base
AUTHOR
Jaroslav Krizek, Oct 25 2011
STATUS
approved