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 A230715 #14 Oct 31 2013 04:11:24 %S A230715 641,656597,6212357,18958567877,287468425241,626160901277, %T A230715 634038307447,1395494019917,1925525109197,1960708164797,1962378065897, %U A230715 1977370759361,2788325761547,3032013857177,4846359321103,6877227801077,11927878640383,20835183400303,22298617759877 %N A230715 Smallest numbers in a set of 4 consecutive odd numbers that are primes or pseudoprime (base 2). %H A230715 Shyam Sunder Gupta, <a href="/A230715/b230715.txt">Table of n, a(n) for n = 1..913</a> %H A230715 Jan Feitsma, <a href="http://www.cecm.sfu.ca/Pseudoprimes/index-2-to-64.html">Tables of pseudoprimes and related data</a> %e A230715 656597 is in sequence because 656597, 656599, 656601, 656603 is a set of 4 consecutive odd number where 656601 is pseudoprime base 2 and others are prime. %o A230715 (PARI) \\ Import A001567 into the vector v %o A230715 for(i=1,#v, start=stop=v[i]; while(ok(start-=2),); while(ok(stop+=2),); while(stop-start>9, print1(start+=2, ", "))) \\ _Charles R Greathouse IV_, Oct 28 2013 %Y A230715 Cf. A001567, A230559, A228575, A230668. %K A230715 nonn %O A230715 1,1 %A A230715 _Shyam Sunder Gupta_, Oct 28 2013