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 A337574 #15 Mar 30 2024 17:12:37 %S A337574 6,31,112,279,652,1231,2140,3363,5132,7647,10600,14583,19754,25435, %T A337574 31894,40617,50866,62583,76174,91431,108124,127319,147868,172493, %U A337574 200392,230281,262140,297413,334756,374607,419958,471113,524892,583853,649458,717339,790760,868997,951672,1039871,1134792 %N A337574 a(n) is the dot product of the vectors of the first n primes and the next n primes. %H A337574 Robert Israel, <a href="/A337574/b337574.txt">Table of n, a(n) for n = 1..10000</a> %F A337574 a(n) = Sum_{k=1..n} prime(k)*prime(n+k). %e A337574 a(3) = 2*7 + 3*11 + 5*13 = 112. %p A337574 P:= <seq(ithprime(i), i=1..500)>: %p A337574 [seq(P[1..t]^%T . P[t+1..2*t],t=1..250)]; %t A337574 Table[Prime[Range[n]].Prime[Range[n+1,2n]],{n,50}] (* _Harvey P. Dale_, Mar 30 2024 *) %o A337574 (PARI) a(n) = sum(k=1, n, prime(k)*prime(n+k)); \\ _Michel Marcus_, Sep 02 2020 %Y A337574 Cf. A000040, A337573 (n such that a(n) is prime). %Y A337574 Cf. A033994 (similar when prime(n) is replaced with n). %K A337574 nonn %O A337574 1,1 %A A337574 _Robert Israel_, Sep 01 2020