This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A107690 #10 Sep 08 2022 08:45:18 %S A107690 41,4111,11411,12211,21121,21211,22111,112121,1114111,11111141, %T A107690 11141111,111112121,111121121,112111211,112112111,121111121,121112111, %U A107690 122111111,212111111,1111111411,1111411111,11111121121,11111121211,11111211121 %N A107690 Primes with digital product = 4. %H A107690 Vincenzo Librandi, <a href="/A107690/b107690.txt">Table of n, a(n) for n = 1..2400</a> %t A107690 Flatten[ Table[ Select[ Sort[ FromDigits /@ Join[ Permutations[ Flatten[{4, Table[1, {n}]}]], Permutations[ Flatten[{2, 2, Table[1, {n - 1}]}] ]]], PrimeQ[ # ] &], {n, 0, 10}]] %o A107690 (Magma) [p: p in PrimesUpTo(10^8) | &*Intseq(p) eq 4]; // _Vincenzo Librandi_, Jun 30 2017 %Y A107690 Cf. A004022, A107612, A107689, A107691, A107692, A107693, A107694, A107695, A107696, A107697, A107698. %Y A107690 Subsequence of A199987. %K A107690 base,nonn %O A107690 1,1 %A A107690 _Zak Seidov_ and _Robert G. Wilson v_, May 20 2005