cp's OEIS Frontend

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.

A118693 Semiprimes which are divisible by the sum of their digits.

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%I A118693 #9 Feb 08 2021 02:59:59
%S A118693 4,6,9,10,21,111,133,201,209,247,407,481,511,629,803,1011,1101,1141,
%T A118693 1387,1417,1651,1679,1853,2119,2159,2353,2771,3031,3077,3097,3383,
%U A118693 3439,3523,3749,3781,4577,4607,5149,5161,5219,5833,6331,6443,7033,7361,7501
%N A118693 Semiprimes which are divisible by the sum of their digits.
%H A118693 Amiram Eldar, <a href="/A118693/b118693.txt">Table of n, a(n) for n = 1..10000</a>
%e A118693 133 is in the sequence because it is a semiprime and it is divisible by the sum of its digits, 1+3+3 = 7.
%t A118693 spQ[n_] := Plus @@ Last /@ FactorInteger@n == 2; Select[Range@7542, spQ@# && IntegerQ[ #/Plus @@ IntegerDigits@# ] &] (* _Robert G. Wilson v_, Jun 10 2006 *)
%Y A118693 Intersection of A001358 and A005349.
%Y A118693 Cf. A118694.
%K A118693 base,nonn
%O A118693 1,1
%A A118693 Luc Stevens (lms022(AT)yahoo.com), May 20 2006
%E A118693 More terms from _Robert G. Wilson v_, Jun 10 2006