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 A295149 #6 Nov 18 2017 04:23:59 %S A295149 5,11,23,33,45,47,49,61,73,85,95,105,117,153,163,165,187,191,195,217, %T A295149 219,229,257,259,269,271,273,283,285,313,325,339,353,363,365,367,369, %U A295149 381,383,385,397,399,401,403,413,427,441,453,481,483,493,495,497,507 %N A295149 Numbers n such that gcd(A002487(n), A002487(n+2)) > 1. %C A295149 All terms are odd (as for any k > 0, gcd(A002487(2*k), A002487(2*k+2)) = gcd(A002487(k), A002487(k+1)) = 1). %C A295149 This sequence is infinite as it contains A055010(n) for any n > 1. %C A295149 For any n > 1, gcd(A002487(A055010(n)), A002487(A055010(n)+2)) = 2*n-1. %C A295149 For any n > 0, gcd(A002487(a(n)), A002487(a(n)+2)) is odd (as A002487(k) is even iff k is divisible by 3). %o A295149 (PARI) fusc(n)=local(a=1, b=0); while(n>0, if(bitand(n, 1), b+=a, a+=b); n>>=1); b \\ after Charles R Greathouse IV at A002487 %o A295149 for (n=1, 507, if (gcd(fusc(n),fusc(n+2))>1, print1 (n", "))) %Y A295149 Cf. A002487, A055010. %K A295149 nonn %O A295149 1,1 %A A295149 _Rémy Sigrist_, Nov 15 2017