# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a076473 Showing 1-1 of 1 %I A076473 #3 Mar 30 2012 18:50:26 %S A076473 0,0,0,0,0,1,1,1,2,0,2,1,3,1,1,1,3,1,4,0,2,1,4,1,4,1,2,1,5,0,6,1,2,1, %T A076473 4,1,7,1,2,0,7,1,8,1,1,1,8,1,7,0,2,1,9,1,7,1,3,1,9,0,10,1,3,1,6,1,10, %U A076473 1,4,0,11,1,11,1,3,1,10,1,12,0,4,1,12,1,9,1,4,1,13,0,10,1,4,1,10,1,14,1,4 %N A076473 Number of pairs (p,q) of successive primes with p+q<=n and gcd(p+q,n)=1. %C A076473 a(n) = A076471(n) - A076472(n). %e A076473 n=27: gcd(2+3,27)=1, gcd(3+5,27)=1, gcd(5+7,27)=3, gcd(7+11,27)=9, gcd(11+13,27)=3, hence a(27)=2. %Y A076473 Cf. A000010. %K A076473 nonn %O A076473 1,9 %A A076473 _Reinhard Zumkeller_, Oct 14 2002 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE