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 A088432 Number of ways to write n as n = u*v*w with 1 <= u < v <= w. 6
 0, 0, 0, 1, 0, 1, 0, 1, 1, 1, 0, 2, 0, 1, 1, 2, 0, 3, 0, 2, 1, 1, 0, 4, 1, 1, 1, 2, 0, 4, 0, 3, 1, 1, 1, 5, 0, 1, 1, 4, 0, 4, 0, 2, 2, 1, 0, 7, 1, 3, 1, 2, 0, 4, 1, 4, 1, 1, 0, 8, 0, 1, 2, 4, 1, 4, 0, 2, 1, 4, 0, 9, 0, 1, 3, 2, 1, 4, 0, 6, 2, 1, 0, 8, 1, 1, 1, 4, 0, 8, 1, 2, 1, 1, 1, 9, 0, 3, 2, 6, 0, 4, 0, 4, 4, 1, 0, 9, 0, 4, 1, 6, 0, 4, 1, 2, 2, 1, 1, 14 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,12 COMMENTS a(n)=0 iff n=1 or n is prime: a(A008578(n)) = 0, a(A002808(n)) > 0. LINKS Antti Karttunen, Table of n, a(n) for n = 1..3003 EXAMPLE n=12: (1,2,6), (1,3,4): therefore a(12)=2; n=18: (1,2,9), (1,3,6), (2,3,3): therefore a(18)=3. PROG (PARI) A088432(n) = { my(s=0); fordiv(n, u, for(v=u+1, n-1, for(w=v, n, if(u*v*w==n, s++)))); (s); }; \\ Antti Karttunen, Aug 24 2017 CROSSREFS Cf. A034836, A088433, A088434, A122179, A122180. Sequence in context: A202177 A029360 A185279 * A329747 A304455 A238951 Adjacent sequences:  A088429 A088430 A088431 * A088433 A088434 A088435 KEYWORD nonn AUTHOR Reinhard Zumkeller, Oct 01 2003 EXTENSIONS Data section extended to 120 terms by Antti Karttunen, Aug 24 2017 STATUS approved

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Last modified February 20 17:41 EST 2020. Contains 332082 sequences. (Running on oeis4.)