|
|
A023550
|
|
Convolution of natural numbers >= 2 and (F(2), F(3), F(4), ...).
|
|
2
|
|
|
2, 7, 16, 32, 59, 104, 178, 299, 496, 816, 1335, 2176, 3538, 5743, 9312, 15088, 24435, 39560, 64034, 103635, 167712, 271392, 439151, 710592, 1149794, 1860439, 3010288, 4870784, 7881131, 12751976, 20633170, 33385211, 54018448, 87403728, 141422247, 228826048
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
LINKS
|
|
|
FORMULA
|
G.f.: x*(2-x)*(1+x) / ((1-x)^2*(1-x-x^2)).
a(n) = (2^(-1-n)*((1-sqrt(5))^n*(-15+7*sqrt(5)) + (1+sqrt(5))^n*(15+7*sqrt(5)))) / sqrt(5) - 2*n - 7.
a(n) = 3*a(n-1) - 2*a(n-2) - a(n-3) + a(n-4) for n>4.
(End)
|
|
MATHEMATICA
|
|
|
PROG
|
(PARI) Vec(x*(2-x)*(1+x)/((1-x)^2*(1-x-x^2)) + O(x^40)) \\ Colin Barker, Mar 11 2017
(PARI) vector(40, n, fibonacci(n+5) + fibonacci(n+3) -2*n-7) \\ G. C. Greubel, Jun 01 2019
(Magma) [Lucas(n+4) - 2*n - 7 : n in [1..40]]; // G. C. Greubel, Jun 01 2019
(Sage) [lucas_number2(n+4, 1, -1) -2*n-7 for n in (1..40)] # G. C. Greubel, Jun 01 2019
(GAP) List([1..40], n-> Lucas(1, -1, n+4)[2] -2*n-7 ) # G. C. Greubel, Jun 01 2019
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|