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 A171612 Integers n such that (25*10^n)+1 is prime. 0
 1, 8, 255, 320, 609, 688, 1436, 3271, 3921, 6520, 19604, 38348, 63531 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS No others less than 20000. See Kamada link - primecount.txt for terms, primesize.txt for discovery details including probable or proved primes - search on "25001". LINKS Table of n, a(n) for n=1..13. Makoto Kamada, List of near-repdigit-related prime numbers. Index entries for primes involving repunits. EXAMPLE For n=8 we have (25*10^8)+1 = 25*100000000+1 = 2500000000+1 = 2500000001, which is prime. CROSSREFS Cf. A056797, A056804, A056805, A056806, A056807 Sequence in context: A213412 A226428 A277421 * A053717 A267250 A034674 Adjacent sequences: A171609 A171610 A171611 * A171613 A171614 A171615 KEYWORD more,nonn AUTHOR Julien Peter Benney (jpbenney(AT)ftml.net), Dec 13 2009 EXTENSIONS Edited by Ray Chandler, Dec 23 2010 a(12)-a(13) from Kamada data by Tyler Busby, May 03 2024 STATUS approved

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Last modified July 15 21:59 EDT 2024. Contains 374334 sequences. (Running on oeis4.)