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A143962
Binomial transform of A066247 (characteristic function of composite numbers).
1
0, 0, 0, 0, 1, 5, 16, 42, 99, 220, 476, 1023, 2201, 4732, 10102, 21284, 44103, 89845, 180354, 358226, 707561, 1396560, 2764906, 5501807, 11005363, 22101301, 44470622, 89475559, 179753753, 360325116, 720748862, 1439561539, 2873846383, 5740501232, 11484167472
OFFSET
0,6
LINKS
N. J. A. Sloane, Transforms
FORMULA
a(n) = Sum_{k=4..n} C(n,k)*A066247(k).
EXAMPLE
a(7) = [35,21,7,1]*[1,0,1,0] = 35+7 = 42.
MAPLE
a:= proc(n) local k, s; s:=0; for k from 4 to n do if not isprime(k) then s:= s+ binomial(n, k) fi od; s; end: seq (a(n), n=0..40);
MATHEMATICA
a[n_] := Module[{k, s = 0}, For[k = 4, k <= n, k++, If[!PrimeQ[k], s = s + Binomial[n, k]]]; s]; Table [a[n], {n, 0, 40}] // Flatten (* Jean-François Alcover, Dec 30 2013, translated from Maple *)
CROSSREFS
Sequence in context: A255135 A055796 A002662 * A321959 A066634 A241794
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Sep 05 2008
STATUS
approved