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A102354 a(n) is the number of ways n can be written as k^2 * j, 0 < j <= k. 8
1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 2, 0, 0, 0, 0, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,64
COMMENTS
Sum_{n>0} a(n)/n = 2*zeta(3). See A152648.
LINKS
FORMULA
a(n) >= A102448(n). - Antti Karttunen, Aug 27 2017
EXAMPLE
a(18) = 1 because 18 = k^2 * j, j <= k, in one way: k=3, j=2.
MATHEMATICA
t = Sort[ Flatten[ Table[k^2*j, {k, 11}, {j, k}]]]; Table[ Count[t, n], {n, 105}] (* Robert G. Wilson v, Feb 22 2005 *)
PROG
(PARI) A102354(n) = sumdiv(n, d, (issquare(d) && (sqrtint(d) >= (n/d)))); \\ Antti Karttunen, Aug 27 2017
CROSSREFS
Sequence in context: A014082 A322583 A351439 * A370222 A372717 A349615
KEYWORD
nonn
AUTHOR
Leroy Quet, Feb 21 2005
EXTENSIONS
More terms from Robert G. Wilson v, Feb 22 2005
STATUS
approved

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Last modified June 20 03:21 EDT 2024. Contains 373512 sequences. (Running on oeis4.)