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 A074908 #6 Feb 02 2025 00:17:33
%S A074908 2,2,2,2,2,2,2,2,2,3,2,2,3,2,2,2,2,3,3,2,3,2,2,2,2,3,3,2,3,3,3,2,3,2,
%T A074908 2,3,2,3,3,3,2,5,2,3,2,2,3,2,2,4,3,2,3,3,3,3,2,3,2,3,5,2,3,2,2,4,2,3,
%U A074908 2,2,4,3,3,3,2,3,2,3,4,4,2,5,2,5,3,2,3,2,2,3,4,3,2,4,2,3,3,2,4,2,3,3,2,2,3
%N A074908 Number of integers with an odd number of distinct primes (for which mu(n)=-1) between two consecutive primes prime(n) and prime(n+1).
%e A074908 Between 7919 and 7927 the 5 numbers which have an odd number of distinct primes are as follows: {7919,7922,7923,7926,7927}, so a(1000)=5.
%p A074908 readlib(issqr): lstmp := proc(n) local t1,i; t1 := 0; for i from ithprime(n) to ithprime(n+1) do if (issqrfree(i) = 'true' and mobius(i)=-1) then t1 := t1+1; fi; od; t1; end: lstmp(200);
%Y A074908 Cf. A061265, A061399.
%K A074908 nonn
%O A074908 1,1
%A A074908 _Jani Melik_, Sep 30 2002
%E A074908 Offset corrected by _Sean A. Irvine_, Feb 01 2025