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 A161183 #12 Mar 07 2023 09:21:53
%S A161183 1,9,16,25,53,78,82,89,115,120,130,152,161,178,196,224,233,235,250,
%T A161183 256,265,286,291,300,301,314,315,325,347,357,360,368,381,391,397,419,
%U A161183 428,430,456,468,479,483,484,494,495,512,528,570,577,589,591,608,610,620
%N A161183 Terms which occur at least twice in A161182.
%C A161183 A161182 is not monotonic, so some terms (like 89) listed here are not direct neighbors in A161182. - _R. J. Mathar_, Jun 22 2009
%p A161183 A038107 := proc(n) numtheory[pi]( n^2) ; end: A078435 := proc(n) n^2-A038107(n) ; end: A161182 := proc(n) A078435(n)-A078435(n-1) ; end: L := [] ; for n from 1 to 1200 do L := [op(L), A161182(n)] ; od: read("transforms3") ; L := sort(L) ; L := LISTDUPL(L,0) ; # _R. J. Mathar_, Jun 22 2009
%t A161183 f[n_] := 2n - 1 - PrimePi[n^2] + PrimePi[(n-1)^2];
%t A161183 Select[Split[Array[f, 1000]//Sort], Length[#] >= 2&][[All, 1]]
%t A161183 (* _Jean-François Alcover_, Mar 07 2023 *)
%Y A161183 Cf. A078435, A161182.
%K A161183 easy,nonn
%O A161183 1,2
%A A161183 _Daniel Tisdale_, Jun 05 2009
%E A161183 Edited by _N. J. A. Sloane_, Jun 07 2009
%E A161183 Missing numbers added by _R. J. Mathar_, Jun 22 2009