1,1

Equivalently, primes of the form 3n + 1.

Primes p dividing sum(k=0,p,C(2k,k)) -3 = A006134(p)-3 - Benoit Cloitre (benoit7848c(AT)orange.fr), Feb 08 2003

Primes p such that tau(p)==2 (mod 3) where tau(x) is the Ramanujan tau function (cf. A000594). - Benoit Cloitre (benoit7848c(AT)orange.fr), May 04 2003

Primes of the form x^2-xy+7y^2 with x and y nonnegative. - T. D. Noe (noe(AT)sspectra.com), May 07 2005

Primes p such that p^2 divides Sum[Sum[(2k)!/(k!)^2,{k,1,m}],{m,1,2(p-1)}]. - Alexander Adamchuk (alex(AT)kolmogorov.com), Jul 04 2006

A039701(A049084(a(n))) = A134323(A049084(a(n))) = 1. - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Oct 21 2007

M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 870.

K. G. Reuschle, Tafeln Complexer Primzahlen. K\"{o}nigl. Akademie der Wissenschaften, Berlin, 1875, p. 1.

T. D. Noe, Table of n, a(n) for n=1..1000

M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, December 1972 [alternative scanned copy].

C. Banderier, Calcul de (-3/p)

A. Granville and G. Martin, Prime number races

a := [ ]: for n from 1 to 400 do if isprime(6*n+1) then a := [ op(a), n ]; fi; od: A002476 := n->a[n];

Select[6*Range[100] + 1, PrimeQ[ # ] &] - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Apr 06 2006

(PARI) \primes of the form 3n+1 f(n) = for(x=1, n, y=3*x + 1; if(isprime(y), print1(y", "))) (from Cino Hilliard (hillcino368(AT)gmail.com), Feb 04 2004)

Cf. A045331.

For values of n see A024899. Primes of form 3n-1 give A003627.

These are the primes arising in A024892, A024899, A034936, A091178 gives prime index.

Adjacent sequences: A002473 A002474 A002475 this_sequence A002477 A002478 A002479

Sequence in context: A038590 A129389 A107925 this_sequence A123365 A040079 A038160

nonn,nice,easy

njas