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 A121614 #9 Feb 13 2021 01:08:47 %S A121614 27,45,54,72,78,87,126,159,162,168,186,195,207,216,234,243,249,261, %T A121614 267,270,276,294,324,342,348,357,375,384,405,423,429,432,438,450,483, %U A121614 492,504,519,537,540,573,591,612,618,621,627,672,678,681,687,702,708,720 %N A121614 Numbers that have composite sum of digits and prime sum of squares of digits. %H A121614 Vincenzo Librandi, <a href="/A121614/b121614.txt">Table of n, a(n) for n = 1..1000</a> %e A121614 For example: the sum of digits of 27 is 9 which is composite; the sum of squares of digits of 27 is 53 which is prime. %t A121614 sod[k_, m_] := Plus @@ (IntegerDigits[k]^m); Select[ Table[n, {n, 1000}], (! PrimeQ[sod[ #, 1]] && PrimeQ[sod[ #, 2]]) &] %Y A121614 Cf. A091362 (Primes p such that the sum of the digits of p is not prime, but the sum of the squares of the digits of p is prime) is a prime subsequence of this sequence. %K A121614 base,nonn %O A121614 1,1 %A A121614 _Tanya Khovanova_, Sep 08 2006