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A120430 Greater of prime powers that differ by 1. In other words, numbers n such that n-1 and n are prime powers. 0
2, 3, 4, 5, 8, 9, 17, 32, 128, 257, 8192, 65537, 131072, 524288, 2147483648, 2305843009213693952, 618970019642690137449562112, 162259276829213363391578010288128 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
See comments in A006549.
LINKS
FORMULA
a(n) = A006549(n) + 1. - Michel Marcus, Aug 25 2013
PROG
(PARI) isokp(n) = (n==1) || isprime(n) || (ispower(n, , &k) && isprime(k));
isok(n) = isokp(n) && isokp(n-1); \\ Michel Marcus, Aug 25 2013
CROSSREFS
Cf. A006549.
Sequence in context: A330400 A306044 A263581 * A295033 A152606 A057911
KEYWORD
nonn
AUTHOR
Greg Huber, Jul 13 2006
STATUS
approved

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Last modified March 29 04:59 EDT 2024. Contains 371264 sequences. (Running on oeis4.)