|
| |
|
|
A364095
|
|
Sum of divisors of 5*n-4 of form 5*k+1.
|
|
4
|
|
|
|
1, 7, 12, 17, 22, 27, 32, 43, 42, 47, 52, 57, 62, 84, 72, 77, 82, 87, 92, 119, 102, 107, 112, 117, 133, 154, 132, 137, 142, 147, 152, 189, 162, 167, 172, 204, 182, 224, 192, 197, 202, 207, 212, 259, 222, 227, 264, 237, 242, 294, 252, 273, 262, 267, 272, 329, 282, 324, 292, 297, 302, 364, 312
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,2
|
|
|
LINKS
|
|
|
|
FORMULA
|
G.f.: Sum_{k>0} (5*k-4) * x^k / (1 - x^(5*k-4)).
|
|
|
MATHEMATICA
|
a[n_] := DivisorSum[5*n - 4, # &, Mod[#, 5] == 1 &]; Array[a, 100] (* Amiram Eldar, Jul 12 2023 *)
|
|
|
PROG
|
(PARI) a(n) = sumdiv(5*n-4, d, (d%5==1)*d);
|
|
|
CROSSREFS
|
|
|
|
KEYWORD
|
nonn
|
|
|
AUTHOR
|
|
|
|
STATUS
|
approved
|
| |
|
|
