1,3

Table of n, a(n) for n=1..26.

Select[Range[0, 2000], PrimeQ[4*7^#+1]&]

Sequence in context: A014689 A117206 A026443 * A032858 A181498 A030703

Adjacent sequences: A204320 A204321 A204322 * A204324 A204325 A204326

nonn

José María Grau Ribas, Jan 14 2012

a(17)-a(26) from Predrag Kurtovic, May 24 2015

approved