|
|
A015489
|
|
a(0)=1, a(1)=4, a(n) = sum_{k=0}^{k=n-1} 4^k a(k).
|
|
0
|
|
|
1, 4, 17, 289, 18785, 4827745, 4948438625, 20273753046625, 332185443668950625, 21770437421732017110625, 5707011317919939625464790625, 5984240806710536532650993759190625
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,2
|
|
LINKS
|
|
|
FORMULA
|
|
|
PROG
|
(Magma) I:=[1, 4, 17]; [n le 3 select I[n] else (4^(n-2)+1)*Self(n-1): n in [1..15]]; // _Vincenzo Librandi, Nov 11 2012
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|