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A025495
Probable extension of A013704.
1
1, 2, 12, 44, 100, 203, 344, 558, 824, 1189, 1620, 2176, 2812, 3599, 4480, 5538, 6704, 8073, 9564, 11284, 13140, 15251, 17512, 20054, 22760, 25773, 28964, 32488, 36204, 40279, 44560, 49226, 54112, 59409, 64940, 70908, 77124, 83803, 90744, 98174
OFFSET
0,2
FORMULA
For n >= 9, a(n) = 3*a(n-1)-a(n-2)-5*a(n-3)+5*a(n-4)+a(n-5)-3*a(n-6)+a(n-7).
O.g.f.: (x^7-x^6+3x^5+7x^4+22x^3+7x^2+1)/((1+x)^2*(x-1)^4) . - R. J. Mathar, May 28 2008
CROSSREFS
Sequence in context: A111389 A203278 A013704 * A028570 A009074 A371487
KEYWORD
nonn,easy
STATUS
approved