OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..500
Index entries for linear recurrences with constant coefficients, signature (30, -125).
FORMULA
a(n) = A000217(A000351(n)-1) = 30*a(n-1)-125*a(n-2). G.f.: 10*x/((25*x-1)*(5*x-1)). - R. J. Mathar, Jul 13 2009
MATHEMATICA
n5[n_]:=Module[{c=5^n}, (c(c-1))/2]; Array[n5, 20, 0] (* or *) LinearRecurrence[ {30, -125}, {0, 10}, 20] (* Harvey P. Dale, Oct 25 2011 *)
PROG
(Magma) [5^n*(5^n-1)/2: n in [0..20]]; // Vincenzo Librandi, Mar 05 2012
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Jul 12 2009
EXTENSIONS
Edited by R. J. Mathar, Jul 13 2009
STATUS
approved