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 A213734 #22 Jan 27 2022 13:04:22 %S A213734 3,7,59,137,277,313,499,563,619,719,787,797,919,937,971,1013,1217, %T A213734 1283,1373,1409,1439,1451,1621,1747,1789,2207,2237,2267,2393,2417, %U A213734 2441,2591,2707,2797,2801,2939,2999,3251,3529,3769,3847,4201,4441,4447,4597,4643,4721 %N A213734 Primes in A213650. %C A213734 Primes p such that the sum of the first p primes is semiprime. %e A213734 7 is in the sequence because the sum of the first 7 primes is 2 + 3 + 5 + 7 + 11 + 13 + 17 = 58 = 2*29, which is semiprime. %p A213734 with(numtheory): for n from 1 to 10000 do:s:=sum(‘ithprime(k)’, ’k’=1..n):if bigomega(s)=2 and type(n,prime)=true then printf(`%d, `, n):else fi:od: %t A213734 Select[Flatten[Position[If[PrimeOmega[#]==2,1,0]&/@Accumulate[ Prime[ Range[ 5000]]],1]],PrimeQ] (* _Harvey P. Dale_, Jan 27 2022 *) %o A213734 (PARI) isok(n) = isprime(n) && bigomega(vecsum(primes(n))) == 2; \\ _Michel Marcus_, Sep 18 2017 %Y A213734 Cf. A213650. %K A213734 nonn %O A213734 1,1 %A A213734 _Michel Lagneau_, Jun 19 2012