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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 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 * A250375 A060889 A206362 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

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