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 A354200 #6 May 23 2022 17:45:36 %S A354200 5,7,13,11,19,17,29,23,31,37,43,41,53,47,59,61,67,73,71,79,89,83,103, %T A354200 97,101,109,107,127,113,137,131,139,149,151,157,163,173,167,179,181, %U A354200 191,193,199,197,229,211,223,227,239,233,241,251,257,263,269,271,277,283,281,293,307,313,311,331,317,337,347,349,359 %N A354200 Prime map that sends 2 to 5, and each 4k+1 and 4k+3 prime to the next larger prime of the same type. %F A354200 For all n >= 1, A354201(A000720(a(n))) = A000040(n). %e A354200 A000040(2) = 3, and the next larger prime of the form 4k+3 is 7, therefore a(2) = 7. %e A354200 A000040(3) = 5, and the next larger prime of the form 4k+1 is 13, therefore a(3) = 13. %e A354200 A000040(4) = 7, and the next larger prime of the form 4k+3 is 11, therefore a(4) = 11. %o A354200 (PARI) A354200(n) = if(1==n,5,my(p=prime(n), m=p%4); forprime(q=1+p,,if(m==(q%4),return(q)))); %Y A354200 Cf. A000040, A000720, A354201, A354202. %K A354200 nonn %O A354200 1,1 %A A354200 _Antti Karttunen_, May 23 2022