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A025931
Expansion of 1/((1-2x)(1-3x)(1-5x)(1-7x)).
2
1, 17, 188, 1726, 14343, 112371, 848506, 6255392, 45386165, 325753285, 2320698744, 16447547298, 116147697667, 818112983159, 5752200695702, 40392496919044, 283383067688049, 1986859807248393, 13923911479636180, 97546847987676230, 683225284523104511
OFFSET
0,2
FORMULA
a(n) = 12*a(n-1) - 35*a(n-2) + 3^(n+1) - 2^(n+1), n >= 2. - Vincenzo Librandi, Mar 19 2011
a(n) = 7^(n+3)/40 - 2^(n+3)/15 + 3^(n+3)/8 - 5^(n+3)/12. - R. J. Mathar, Mar 19 2011
MAPLE
b:= proc(n, k) option remember; `if`(n=0, 1,
`if`(k=0, 0, ithprime(k)*b(n-1, k)+b(n, k-1)))
end:
a:= n-> b(n, 4):
seq(a(n), n=0..28); # Alois P. Heinz, Jul 14 2021
MATHEMATICA
CoefficientList[Series[1/((1-2x)(1-3x)(1-5x)(1-7x)), {x, 0, 20}], x] (* or *) LinearRecurrence[{17, -101, 247, -210}, {1, 17, 188, 1726}, 20] (* Harvey P. Dale, Aug 05 2013 *)
CROSSREFS
Column k=4 of A343751.
Sequence in context: A225966 A057614 A041548 * A115234 A197370 A211848
KEYWORD
nonn,easy
STATUS
approved