|
|
A141023
|
|
a(n) = 2^n - (3-(-1)^n)/2.
|
|
4
|
|
|
0, 0, 3, 6, 15, 30, 63, 126, 255, 510, 1023, 2046, 4095, 8190, 16383, 32766, 65535, 131070, 262143, 524286, 1048575, 2097150, 4194303, 8388606, 16777215, 33554430, 67108863, 134217726, 268435455, 536870910, 1073741823, 2147483646, 4294967295, 8589934590, 17179869183
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,3
|
|
LINKS
|
|
|
FORMULA
|
G.f.: 3*x^2/( (x-1)*(2*x-1)*(1+x) ). - R. J. Mathar, Jul 07 2011
|
|
MATHEMATICA
|
Range[0, 20]! CoefficientList[Series[D[(Cosh[x]-1)(Exp[x]-1), x], {x, 0, 20}], x] (* Geoffrey Critzer, Dec 03 2011 *)
|
|
PROG
|
(PARI) x='x+O('x^50); concat([0, 0], Vec(3*x^2/((x-1)*(2*x-1)*(1+x)))) \\ G. C. Greubel, Oct 10 2017
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|