A107690 Primes with digital product = 4.

41, 4111, 11411, 12211, 21121, 21211, 22111, 112121, 1114111, 11111141, 11141111, 111112121, 111121121, 112111211, 112112111, 121111121, 121112111, 122111111, 212111111, 1111111411, 1111411111, 11111121121, 11111121211, 11111211121

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..2400

Mathematica

Flatten[ Table[ Select[ Sort[ FromDigits /@ Join[ Permutations[ Flatten[{4, Table[1, {n}]}]], Permutations[ Flatten[{2, 2, Table[1, {n - 1}]}] ]]], PrimeQ[ # ] &], {n, 0, 10}]]

Prog

(Magma) [p: p in PrimesUpTo(10^8) | &*Intseq(p) eq 4]; // Vincenzo Librandi, Jun 30 2017

Crossrefs

Cf. A004022, A107612, A107689, A107691, A107692, A107693, A107694, A107695, A107696, A107697, A107698.

Subsequence of A199987.

Sequence in context: A209097 A233015 A282054 * A068815 A093174 A280677

Adjacent sequences: A107687 A107688 A107689 * A107691 A107692 A107693

Keyword

base,nonn

Author

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

Status

approved