|
|
A140730
|
|
a(4*n)=5^n, a(4*n+1)=2*5^n, a(4*n+2)=3*5^n, a(4*n+3)=4*5^n.
|
|
7
|
|
|
1, 2, 3, 4, 5, 10, 15, 20, 25, 50, 75, 100, 125, 250, 375, 500, 625, 1250, 1875, 2500, 3125, 6250, 9375, 12500, 15625, 31250, 46875, 62500, 78125, 156250, 234375, 312500, 390625, 781250, 1171875, 1562500, 1953125, 3906250, 5859375, 7812500
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,2
|
|
LINKS
|
|
|
FORMULA
|
a(n+1) = a(n) + a(n - n mod 4).
O.g.f.: (1+2*x+3*x^2+4*x^3)/(1-5*x^4). - R. J. Mathar, May 31 2008
a(n) = (n+1-4*floor(n/4))*5^floor(n/4). - Luce ETIENNE, Aug 05 2015
a(n) = 5*a(n-4) for n>3; a(n) = n+1 for n<5. - Bruno Berselli, Aug 05 2015
|
|
MATHEMATICA
|
Table[(n + 1 - 4 Floor[n/4]) 5^Floor[n/4], {n, 0, 40}] (* Bruno Berselli, Aug 05 2015 *)
LinearRecurrence[{0, 0, 0, 5}, {1, 2, 3, 4}, 40] (* Harvey P. Dale, Jul 01 2022 *)
|
|
PROG
|
(Python)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|