|
%I #6 Jul 25 2020 18:01:09
%S 177,377,707,717,737,767,771,778,779,3777,4777,5777,7277,7377,7737,
%T 7747,7771,7773,7778,7779,7787,7977,8777,9777,17777,37777,57777,70777,
%U 77177,77277,77677,77757,77767,77771,277777,577777,677777,707777,737777
%N Near-repdigit semiprimes with 7 as repeated digit.
%H Harvey P. Dale, <a href="/A105988/b105988.txt">Table of n, a(n) for n = 1..1000</a>
%e a(2)=377 is a term because 377 is a semiprime and all digits are equal to 7 except one.
%t Rest[Flatten[Table[Select[FromDigits/@Flatten[Permutations/@Table[ PadRight[ {n},k,7],{n,0,9}],1],PrimeOmega[#]==2&],{k,3,7}]]]//Union (* _Harvey P. Dale_, Jul 25 2020 *)
%K base,nonn
%O 1,1
%A _Shyam Sunder Gupta_, Apr 29 2005
|
