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 A256737 #17 Dec 17 2023 11:28:09 %S A256737 0,1,1,1,5,5,1,5,1,3,5,5,3,3,3,3,1,1,5,5,1,1,1,11,1,5,9,5,1,3,9,3,3,5, %T A256737 1,5,5,3,7,7,1,1,3,7,1,11,3,3,11,17,9,5,5,5,1,5,1,9,3,5,11,5,9,9,5,3, %U A256737 5,7,13,11,9,3,9,3,3,3,3,3,9,3,5,3,5,5,3,1,1,9,9,5,3,3,5,5,21 %N A256737 Number of composites lying between successive pairs of primes, beginning with pair (2,3). Bisection of A046933. %e A256737 For the third term in the sequence, use prime pair (11,13). Only composite that lies between is "12", thus the third value in the sequence is "1". %t A256737 Flatten[Differences/@Partition[Prime[Range[200]],2]]-1 (* _Harvey P. Dale_, Dec 17 2023 *) %o A256737 (PARI) a(n)=my(q=prime(2*n)); q-precprime(q-1)-1 \\ _Charles R Greathouse IV_, Apr 21 2015 %Y A256737 Complement of A256736 with respect to A046933. %K A256737 nonn %O A256737 1,5 %A A256737 _Peter Woodward_, Apr 09 2015