|
|
A279787
|
|
Twice-partitioned numbers where the first partition is constant.
|
|
38
|
|
|
1, 1, 3, 4, 10, 8, 29, 16, 64, 58, 124, 57, 469, 102, 489, 763, 1597, 298, 3858, 491, 8942, 6355, 6187, 1256, 59076, 18766, 20830, 49694, 167078, 4566, 481186, 6843, 752128, 362907, 231592, 1597802, 5951007, 21638, 790404, 2655810, 25274798, 44584, 40898731
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,3
|
|
LINKS
|
|
|
FORMULA
|
|
|
EXAMPLE
|
The a(4)=10 twice-partitions are:
((4)), ((31)), ((22)), ((211)), ((1111)),
((2)(2)), ((2)(11)), ((11)(2)), ((11)(11)),
((1)(1)(1)(1)).
|
|
MAPLE
|
with(numtheory): with(combinat):
a:= proc(n) option remember; `if`(n=0, 1,
add(numbpart(n/d)^d, d=divisors(n)))
end:
|
|
MATHEMATICA
|
nn=20; Table[DivisorSum[n, Power[PartitionsP[#], n/#]&], {n, nn}]
|
|
PROG
|
(PARI) a(n)=if(n==0, 1, sumdiv(n, d, numbpart(n/d)^d)) \\ Andrew Howroyd, Aug 26 2018
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|