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A167186 Record gaps between nonprime prime powers. 3
3, 4, 7, 9, 17, 40, 41, 74, 151, 307, 312, 408, 424, 912, 1032, 1217, 1872, 2518, 3713, 4920, 5208, 8400, 8520, 8892, 9297, 12840, 16008, 21840, 24360, 35880, 38808, 80760, 102168, 129480, 167160, 183960, 201072, 258720, 290760, 301242, 358848, 375468, 415920 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Donovan Johnson, Table of n, a(n) for n = 1..200

EXAMPLE

17 is in the sequence since A025475(9) - A025475(8) = 49 - 32 = 17, and no previous gap is larger.

A025475(10) - A025475(9) = 64 - 49 = 15, but the previous gap is larger, so 15 is not in the sequence.

PROG

(PARI) isA025475(n) = (omega(n) == 1 & !isprime(n)) | (n == 1)

d_max=0; n_prev=1; for(n=2, 32e6, if(isA025475(n), d=n-n_prev; n_prev=n; if(d>d_max, print(d); d_max=d)))

CROSSREFS

List of nonprime prime powers: A025475.

Gaps between nonprime prime powers: A053707.

Record gaps between prime powers including primes: A121492.

Sequence in context: A108796 A048849 A076211 * A221212 A218278 A101062

Adjacent sequences:  A167183 A167184 A167185 * A167187 A167188 A167189

KEYWORD

nonn

AUTHOR

Michael B. Porter, Oct 29 2009, Oct 31 2009, Nov 03 2009

STATUS

approved

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Last modified December 3 18:47 EST 2016. Contains 278745 sequences.