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 A176888 #7 Dec 29 2024 21:20:43 %S A176888 1,2,12,16,18,28,30,36,40,42,52,60,66,70,72,78,88,96,100,102,108,112, %T A176888 126,130,136,138,148,150,156,162,172,180,190,192,196,198,210,222,228, %U A176888 232,238,240,250,256,268,270,276,280,282,292,306,310,312,316,330,336 %N A176888 Unsafe primes minus 1. %C A176888 Non-semiprimes k such that k+1 is a prime. %F A176888 a(n) = A059456(n) - 1. %F A176888 a(n) ~ n log n. - _Charles R Greathouse IV_, Dec 29 2024 %t A176888 Select[Prime[Range[70]]-1,PrimeOmega[#]!=2&] (* _Harvey P. Dale_, Jan 14 2015 *) %o A176888 (PARI) is(n)=isprime(n+1) && !isprime(n\2) \\ _Charles R Greathouse IV_, Dec 29 2024 %Y A176888 Intersection of A006093 and A100959. %K A176888 nonn %O A176888 1,2 %A A176888 _Juri-Stepan Gerasimov_, Apr 28 2010 %E A176888 Entries checked by _R. J. Mathar_, May 06 2010