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A088340
Numbers k such that frac(x^k) = frac(x*frac(x^(k-1))) where x=5/2 and frac(x) denotes the fractional part of x.
1
0, 2, 3, 7, 8, 10, 11, 13, 16, 17, 18, 20, 21, 23, 25, 27, 29, 31, 34, 35, 36, 39, 40, 41, 44, 46, 48, 49, 50, 52, 53, 59, 60, 62, 63, 69, 70, 71, 72, 76, 77, 78, 79, 82, 84, 86, 88, 89, 90, 92, 93, 99, 100, 101, 104, 105, 107, 108, 110, 111, 114, 115, 116, 118, 124, 125
OFFSET
1,2
LINKS
FORMULA
a(n) appears to be asymptotic to 2*n and a(n)=2n for infinitely many values of n such as n=82, 89, 130, 138, 600, 604, 645, ... - Corrected by Robert Israel, Jan 20 2022
MAPLE
filter:= n -> frac((5/2)^n) = frac(5/2*frac((5/2)^(n-1))):select(filter, [$0..1000]); # Robert Israel, Jan 20 2022
CROSSREFS
Sequence in context: A129341 A115985 A131210 * A288696 A163517 A047532
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Nov 07 2003
STATUS
approved