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A143012 Numbers of the form (4^p + 2^p + 1)/7, where p > 3 is prime. 1
151, 2359, 599479, 9588151, 2454285751, 39268347319, 10052678938039, 41175768098368951, 658812288653553079, 2698495133088002829751, 690814754065816531725751, 11053036065049294753459639, 2829577232652317876553477559, 11589948344943812957569751412151 (list; graph; refs; listen; history; text; internal format)
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
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
Sequence in context: A130870 A340436 A211555 * A250375 A060889 A206362
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

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Last modified June 18 14:09 EDT 2024. Contains 373481 sequences. (Running on oeis4.)