A143012 Numbers of the form (4^p + 2^p + 1)/7, where p > 3 is prime.

151, 2359, 599479, 9588151, 2454285751, 39268347319, 10052678938039, 41175768098368951, 658812288653553079, 2698495133088002829751, 690814754065816531725751, 11053036065049294753459639, 2829577232652317876553477559, 11589948344943812957569751412151

Offset

1,1

Comments

If 8^p-1 is squarefree then the terms of the sequence are either primes (A000040) or overpseudoprimes to base 2 (A141232). In particular, composite numbers of the sequence are strong pseudoprimes to base 2 (A001262). E.g., a(5)=2454285751 is A001262(1828).

Links

Table of n, a(n) for n=1..14.

V. Shevelev, Process of "primoverization" of numbers of the form a^n-1, arXiv:0807.2332 [math.NT], 2008.

Maple

p:=ithprime: seq((4^p(n)+2^p(n)+1)*1/7, n=3..14); # Emeric Deutsch, Aug 16 2008

Mathematica

(4^#+2^#+1)/7&/@Prime[Range[3, 30]] (* Harvey P. Dale, Feb 19 2013 *)

Crossrefs

Cf. A001262, A141232, A000040, A126614.

Sequence in context: A130870 A340436 A211555 * A375332 A250375 A060889

Adjacent sequences: A143009 A143010 A143011 * A143013 A143014 A143015

Keyword

nonn

Author

Vladimir Shevelev, Jul 15 2008, Jul 21 2008

Extensions

Extended by Emeric Deutsch, Aug 16 2008

More terms from Harvey P. Dale, Feb 19 2013

Status

approved