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 A084421 #7 Apr 14 2023 15:47:22 %S A084421 3,4,8,11,19,23,32,35,42,54,57,71,79,82,89,102,113,117,131,138,143, %T A084421 153,162,174,191,198,201,209,213,222,247,259,271,274,294,297,309,322, %U A084421 329,341,353,357,375,383,390,393,417,439,449,453,461,471,477,495,512 %N A084421 a(n) = A005187(A000040(n)). %e A084421 A000040(6)=13 -> [13/2]=6 -> [6/2]=3 -> [3/2]=1 %e A084421 .......... 13 -> 13+6=19 -> 19+3=22 -> 22+1=23=a(6). %p A084421 A084421 := proc(n) %p A084421 A005187(ithprime(n)) ; %p A084421 end proc: %p A084421 seq(A084421(n),n=1..55) ; # _R. J. Mathar_, Jul 09 2016 %Y A084421 Cf. A000040, A005187, A035100. %K A084421 nonn %O A084421 1,1 %A A084421 _Reinhard Zumkeller_, Jun 26 2003