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 A056160 #19 Jul 26 2025 03:18:08 %S A056160 1,2,2,3,2,3,5,5,5,5,3,7,4,4,6,7,6,5,5,6,4,7,5,5,5,4,8,8,7,6,8,6,9,5, %T A056160 6,6,9,8,9,5,11,7,9,7,9,10,11,4,9,6,7,7,7,6,8,9,8,12,7,8,8,9,7,6,8,6, %U A056160 9,4,8,7,12,10,7,8,7,7,10,8,9,7,9 %N A056160 Sum of A054988 and A054989. %C A056160 Prime divisors are counted with multiplicity. %C A056160 If "2" were a cluster point of this sequence it would follow that there are infinitely many twin primes. %H A056160 Amiram Eldar, <a href="/A056160/b056160.txt">Table of n, a(n) for n = 1..98</a> %o A056160 (PARI) a(n) = my(P=prod(k=1, n, prime(k))); bigomega(P+1) + bigomega(P-1); \\ _Michel Marcus_, Mar 07 2022 %Y A056160 Cf. A054988, A054989. %K A056160 hard,nonn %O A056160 1,2 %A A056160 Arne Ring (arne.ring(AT)epost.de), Aug 01 2000 %E A056160 a(36)-a(81) from _Charles R Greathouse IV_, May 07 2011