OFFSET
0,2
COMMENTS
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..10000
R. Zumkeller, Enumerations of Divisors
Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).
FORMULA
a(n) = C(n,0) + C(n,1) + 10*C(n,2) - 8*C(n,3).
G.f.: (1-2*x+11*x^2-18*x^3)/(1-x)^4. - Bruno Berselli, Jul 17 2011
EXAMPLE
Differences of divisors of 26 to compute the coefficients of their interpolating polynomial, see formula:
1 2 13 26
1 11 13
10 2
-8
MATHEMATICA
LinearRecurrence[{4, -6, 4, -1}, {1, 2, 13, 26}, 40] (* Harvey P. Dale, Jul 02 2017 *)
PROG
(Magma) [(-4*n^3 + 27*n^2 - 20*n + 3)/3: n in [0..40]]; // Vincenzo Librandi, Jul 17 2011
(PARI) x='x+O('x^50); Vec((1-2*x+11*x^2-18*x^3)/(1-x)^4) \\ G. C. Greubel, Jul 16 2017
CROSSREFS
KEYWORD
sign,easy
AUTHOR
Reinhard Zumkeller, Jun 17 2009
STATUS
approved