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 A164573 Numbers n such that n and n+5 are prime powers. 6
 2, 3, 4, 8, 11, 27, 32, 59, 251, 1019, 2048, 4091, 262139, 1048571, 67108859, 4294967291, 68719476731, 140737488355328, 9007199254740992, 72057594037927931, 73786976294838206459, 332306998946228968225951765070086139 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Numbers n such that n + (0, 5) is a prime power pair. n + (0, 2m), m >= 1, being an admissible pattern for prime pairs, since (0, 2m) = (0, 0) (mod 2), has high density. n + (0, 2m-1), m >= 1, being a non-admissible pattern for prime pairs, since (0, 2m-1) = (0, 1) (mod 2), has low density [the only possible pairs are (2^a - 2m-1, 2^a) or (2^a, 2^a + 2m-1), a >= 0.] Numbers n such that n and n+5 are primes would give only 2, for the prime pair (2, 7). 10^18 < a(21) <= 73786976294838206459. - Donovan Johnson, Aug 17 2009 LINKS Charles R Greathouse IV, Table of n, a(n) for n = 1..37 PROG (PARI) is(n)=if(n<5, return(n>1)); isprimepower(n) && isprimepower(n+5) \\ Charles R Greathouse IV, Apr 24 2015 (PARI) v=List(); for(n=0, 1e3, if(isprimepower(2^n-5), listput(v, 2^n-5)); if(isprimepower(2^n+5), listput(v, 2^n))); Set(v) \\ Charles R Greathouse IV, Apr 24 2015 CROSSREFS Cf. A006549 Numbers n such that n and n+1 are prime powers. Cf. A120431 Numbers n such that n and n+2 are prime powers. Cf. A164571 Numbers n such that n and n+3 are prime powers. Cf. A164572 Numbers n such that n and n+4 are prime powers. Cf. A164573 Numbers n such that n and n+5 are prime powers. Cf. A164574 Numbers n such that n and n+6 are prime powers. Sequence in context: A280195 A286224 A245388 * A004045 A064418 A171164 Adjacent sequences:  A164570 A164571 A164572 * A164574 A164575 A164576 KEYWORD nonn AUTHOR Daniel Forgues, Aug 16 2009 EXTENSIONS Edited by Daniel Forgues, Aug 17 2009 a(13)-a(20) from Donovan Johnson, Aug 17 2009 a(21)-a(22) from Charles R Greathouse IV, Apr 24 2015 STATUS approved

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Last modified February 20 07:41 EST 2020. Contains 332069 sequences. (Running on oeis4.)