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A107698 Smallest prime whose digital product = n or 0 if impossible. 14
11, 2, 3, 41, 5, 23, 7, 181, 19, 251, 0, 43, 0, 127, 53, 281, 0, 29, 0, 541, 37, 0, 0, 83, 11551, 0, 139, 47, 0, 523, 0, 1481, 0, 0, 157, 149, 0, 0, 0, 12451, 0, 67, 0, 0, 59, 0, 0, 283, 11177, 2551, 0, 0, 0, 239, 0, 1187, 0, 0, 0, 1453, 0, 0, 79, 881, 0, 0, 0, 0, 0, 257, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Zeros appear at A068191.

LINKS

Table of n, a(n) for n=1..71.

EXAMPLE

a(20)=541 because 5*4*1=20 and there is no prime less than a(20) which exhibits this characteristic.

MATHEMATICA

f[n_] := If[ Max[ First /@ FactorInteger[n]] > 7, 0, p = 1; While[Times @@ IntegerDigits[ Prime[p]] != n, p++ ]; Prime[p]]; Table[ f[n], {n, 30}]

CROSSREFS

Cf. A004022, A107612, A107689, A107690, A107691, A107692, A107693, A107694, A107695, A107696, A107697.

Sequence in context: A088277 A089744 A160137 * A068164 A089754 A110743

Adjacent sequences:  A107695 A107696 A107697 * A107699 A107700 A107701

KEYWORD

base,nonn

AUTHOR

Zak Seidov and Robert G. Wilson v, May 20 2005

STATUS

approved

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Last modified October 1 15:05 EDT 2020. Contains 337443 sequences. (Running on oeis4.)