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A025796
Expansion of 1/((1-x^2)(1-x^3)(1-x^6)).
0
1, 0, 1, 1, 1, 1, 3, 1, 3, 3, 3, 3, 6, 3, 6, 6, 6, 6, 10, 6, 10, 10, 10, 10, 15, 10, 15, 15, 15, 15, 21, 15, 21, 21, 21, 21, 28, 21, 28, 28, 28, 28, 36, 28, 36, 36, 36, 36, 45, 36, 45, 45, 45, 45, 55, 45, 55, 55, 55, 55, 66
OFFSET
0,7
FORMULA
a(6n) = a(6n+2) = a(6n+3) = a(6n+4) = a(6n+5) = n*(n+1)/2. a(6n+1) = (n-1)*n/2. - Franklin T. Adams-Watters, Oct 27 2014
PROG
(PARI) a(n)=(n^2+(4*((n+2)%3)+7+3*(-1)^n)*n+57+33*(-1)^n/2)\72 \\ Tani Akinari, Oct 27 2014
CROSSREFS
Cf. A024163.
Sequence in context: A068074 A063195 A334070 * A024163 A029155 A042951
KEYWORD
nonn,easy
AUTHOR
STATUS
approved