|
|
A293636
|
|
a(1) = a(2) = 1; a(n) = ( Sum_{i|(n-1)} a(i) ) + Sum_{j|(n-2)} a(j).
|
|
0
|
|
|
1, 1, 3, 6, 12, 21, 39, 66, 114, 192, 324, 531, 888, 1452, 2382, 3891, 6363, 10329, 16833, 27303, 44349, 71907, 116625, 188859, 306114, 495615, 802632, 1299255, 2103504, 3404259, 5510376, 8917248, 14431590, 23353131, 37791414, 61150962, 98953434, 160115403, 259085673, 419218803
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,3
|
|
LINKS
|
|
|
FORMULA
|
a(n) ~ c*phi^n, where phi is the golden ratio (A001622) and c = 1.83226227102725... (conjecture).
|
|
MATHEMATICA
|
a[n_] := a[n] = Sum[a[i], {i, Divisors[n - 1]}] + Sum[a[j], {j, Divisors[n - 2]}]; a[1] = a[2] = 1; Table[a[n], {n, 1, 40}]
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|