cp's OEIS Frontend

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.

A098968 Record values for size of sea of composite numbers surrounding primes.

This page as a plain text file.
%I A098968 #12 May 25 2025 11:54:44
%S A098968 0,1,2,4,8,10,12,16,22,26,38,40,42,46,48,54,56,70,74,78,80,98,112,114,
%T A098968 124,136,138,158,188,198,232,234,244,246,268,304,326,328,334,338,370
%N A098968 Record values for size of sea of composite numbers surrounding primes.
%C A098968 For a prime p let s(p) (essentially A046930) denote the number of composite numbers less than p and greater than max{1, previous prime} or greater than p and less than the next prime. Sequence gives record values of s(p).
%t A098968 a = {1, 2}; b = {0, 1}; d = 1; p = 2; q = 3; Do[ r = Prime[n]; c = r - p - 2; If[c > d, Print[{n + 1, c}]; d = c; AppendTo[a, n - 1]; AppendTo[b, c]]; p = q; q = r, {n, 3, 10^9}]; b (* _Robert G. Wilson v_, Oct 27 2004 *)
%t A098968 Join[{0},DeleteDuplicates[Total/@Partition[Differences[Prime[Range[5*10^6]]]-1,2,1],GreaterEqual]] (* The program generates the first 34 terms of the sequence. *) (* _Harvey P. Dale_, May 25 2025 *)
%Y A098968 Records in A046930 (if initial term is 0 not 1). Cf. A098969, A046931.
%K A098968 nonn
%O A098968 0,3
%A A098968 _N. J. A. Sloane_, Oct 24 2004
%E A098968 More terms from _Robert G. Wilson v_ and _Olaf Voß_, Oct 27 2004