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 A088251 #10 Oct 19 2017 03:14:24 %S A088251 2,2,3,331,10831,25411,512821,512821,12960606121,434491727671, %T A088251 1893245380951,71023095613471,878232256181281 %N A088251 A088250(n) + 1. %C A088251 The n-th row of the following triangle contains smallest set of n primes which form n successive terms of an arithmetic progression from the 2nd to (n+1)th term with the first term 1. 2 2 3 3 5 7 331 661 991 1321 ... Sequence contains the first column. %C A088251 Conjecture: (1) Sequence is infinite. (2) For every n there are infinitely many arithmetic progressions with n successive primes. %C A088251 Minimal primes p beginning a chain of n primes in an arithmetic progression of common difference p-1. - _Robin Garcia_, Jun 22 2013 %C A088251 Least prime p such that pi = i*p-i+1 is prime for i = 2 to i = n. - _Robin Garcia_, Jun 22 2013 %C A088251 a(n) is 1 mod 10 for n > 3 because if p is 3 mod 10, then all (2+5*t)*p -(1+5*t) for t=0,1,2,... are 5 mod 10; if p is 7 mod 10, all (4+5*t)*p -(3+5*t) are 5 mod 10 for t=0,1,2...; if p is 9 mod 10, all (3+5*t)*p - (2+5*t) are 5 mod 10 for t=0,1,2... - _Robin Garcia_, Jun 22 2013 %e A088251 The n-th row of the following triangle contains smallest set of n primes which form n successive terms of an arithmetic progression from the 2nd to (n+1)-st term with the first term 1. %e A088251 2 %e A088251 2 3 %e A088251 3 5 7 %e A088251 331 661 991 1321 %e A088251 ... %e A088251 Sequence contains the first column. %Y A088251 Cf. A002110, A088250, A088252. %K A088251 nonn %O A088251 1,1 %A A088251 _Amarnath Murthy_, Sep 26 2003 %E A088251 More terms from _Don Reble_ and _Farideh Firoozbakht_, Feb 17 2004