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 A087370 #34 Jan 30 2021 11:42:53 %S A087370 1,2,4,6,8,10,14,16,18,20,24,28,30,34,36,38,44,46,50,56,58,60,64,66, %T A087370 76,78,80,84,86,88,90,94,98,104,106,116,118,120,128,130,134,140,144, %U A087370 148,150,154,156,160,164,168,170,174,186,188,190,196,198,200,206,214,216 %N A087370 Numbers n such that 3n - 1 is a prime. %C A087370 3*n - 1 is an Eisenstein prime. - _Vincenzo Librandi_, Aug 08 2010 %C A087370 For all elements of this sequence there are no pairs (x,y) of positive integers such that a(n) = 3*x*y - x + y. - _Pedro Caceres_, Jan 28 2021 %D A087370 M. Cerasoli, F. Eugeni and M. Protasi, Elementi di Matematica Discreta, Bologna 1988 %D A087370 Emanuele Munarini and Norma Zagaglia Salvi, Matematica Discreta, UTET, CittaStudiEdizioni, Milano 1997 %H A087370 Reinhard Zumkeller, <a href="/A087370/b087370.txt">Table of n, a(n) for n = 1..10000</a> %F A087370 a(n)= A024893(n) + 1 = A088879(n) + 2. %o A087370 (Haskell) %o A087370 a087370 n = a087370_list !! (n-1) %o A087370 a087370_list = filter ((== 1) . a010051' . subtract 1 . (* 3)) [0..] %o A087370 -- _Reinhard Zumkeller_, Jul 03 2015 %Y A087370 A003627 gives primes, A091177 gives prime index. %Y A087370 Cf. A010051, subsequence of A016789, A259645. %K A087370 easy,nonn %O A087370 1,2 %A A087370 _Giovanni Teofilatto_, Oct 21 2003 %E A087370 Corrected and extended by _Ray Chandler_, Oct 22 2003