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 A322668 #41 Mar 01 2019 10:52:41 %S A322668 1,350,6497,12317,133787,181427,404471,439097,485237,501182,549378, %T A322668 1410119,2696807,6220607,6827369,6954767,9770027,10302419,10449347, %U A322668 10887977,11014007,16745387,18959111,25883519,27334469,39508037,40311149,40551617,42561437,44592209 %N A322668 Numbers k such that (k, k+2) are not twin primes yet sigma(k+2)/d(k+2) - sigma(k)/d(k) = 1. %C A322668 A variation of A050507 with average of the divisors instead of their sum. %H A322668 Amiram Eldar, <a href="/A322668/b322668.txt">Table of n, a(n) for n = 1..241</a> (terms below 10^10) %t A322668 f[n_] := DivisorSigma[1, n]/DivisorSigma[0, n]; aQ[n_] := f[n + 2] - f[n] == 1 && !(PrimeQ[n] && PrimeQ[n + 2]); Select[Range[1000000], aQ] %o A322668 (PARI) isok(k) = !(isprime(k) && isprime(k+2)) && (sigma(k+2)/numdiv(k+2) - sigma(k)/numdiv(k) == 1); \\ _Michel Marcus_, Jan 22 2019 %Y A322668 Cf. A000005 (number of divisors), A000203 (sum of divisors). %Y A322668 Cf. A050507, A056774, A057020, A057021, A238380. %K A322668 nonn %O A322668 1,2 %A A322668 _Amiram Eldar_, Jan 11 2019