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 A097330 #20 May 08 2021 23:37:36 %S A097330 1,1,1,2,2,3,3,4,5,6,6,7,8,9,9,10,11,12,14,15,15,16,18,19,20,21,21,22, %T A097330 23,24,26,27,29,30,30,31,33,34,35,36,36,37,39,40,41,42,44,45,48,49,50, %U A097330 51,51,52,53,54,54,55,56,57,63,64,65,66,68,69,69,70,74,75,75,76,78,79 %N A097330 In the sequence of prime numbers replace each term p with floor(p/2) and ceiling(p/2). %C A097330 a(2*n-1) + a(2*n) = A000040(n); %C A097330 a(2*n) + a(2*n+1) = A024675(n-1) for n > 1; %C A097330 a(2*n+1) = A005097(n), a(2*(n+1)) = A006254(n). %C A097330 This is a subsequence of A180108. - _Parthasarathy Nambi_, Aug 14 2010 %C A097330 Sum_{n>=1} (-1)^a(n) * log(a(n)) = log(2). - _Dimitris Valianatos_, Jun 14 2016 %F A097330 a(n) = 1 if n < 3, otherwise (prime((n + (n mod 2))/2) + 1)/2 - n mod 2. %e A097330 __ 2; __ 3; __ 5; __ 7; _ 11; _ 13; _ 17; __ 19; ... %e A097330 1, 1; 1, 2; 2, 3; 3, 4; 5, 6; 6, 7; 8, 9; 9, 10; ... %e A097330 1, 1, 1, 2, 2, 3, 3, 4, 5, 6, 6, 7, 8, 9, 9, 10, .... %o A097330 (PARI) a(n)=if(n<3,return(1),return((prime((n+n%2)/2)+1)/2-n%2)); \\ _Dimitris Valianatos_, Jun 14 2016 %K A097330 nonn %O A097330 1,4 %A A097330 _Reinhard Zumkeller_, Sep 17 2004