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A060416
a(n) = n*4^n - 1.
7
1, 3, 31, 191, 1023, 5119, 24575, 114687, 524287, 2359295, 10485759, 46137343, 201326591, 872415231, 3758096383, 16106127359, 68719476735, 292057776127, 1236950581247, 5222680231935, 21990232555519, 92358976733183
OFFSET
0,2
LINKS
Amelia Carolina Sparavigna, Some Groupoids and their Representations by Means of Integer Sequences, International Journal of Sciences (2019) Vol. 8, No. 10.
FORMULA
G.f.: (1-6*x+28*x^2-32*x^3)/((1-x)*(1-4*x)^2). [Colin Barker, Apr 22 2012]
MATHEMATICA
CoefficientList[Series[(1 - 6 x + 28 x^2 - 32 x^3)/((1 - x) (1 - 4 x)^2), {x, 0, 21}], x] (* Michael De Vlieger, Jan 04 2020 *)
PROG
(PARI) { for (n=0, 200, write("b060416.txt", n, " ", abs(n*4^n - 1)); ) } \\ Harry J. Smith, Jul 04 2009
CROSSREFS
Sequence in context: A007233 A197892 A198009 * A333368 A060425 A203242
KEYWORD
nonn,easy
AUTHOR
Jason Earls, Apr 05 2001
STATUS
approved