|
|
A309348
|
|
Sums of two refactorable numbers whose product is refactorable.
|
|
0
|
|
|
2, 3, 9, 10, 11, 13, 14, 17, 19, 20, 21, 25, 36, 37, 38, 41, 42, 44, 49, 52, 57, 58, 60, 61, 64, 65, 68, 72, 73, 76, 80, 81, 84, 85, 88, 89, 92, 96, 97, 98, 100, 104, 105, 108, 109, 113, 116, 117, 120, 124, 126, 128, 129, 132, 133, 136, 137, 140, 144, 145
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
LINKS
|
|
|
MATHEMATICA
|
Flatten[Table[If[Sum[ (1 - Ceiling[(i (n - i))/DivisorSigma[0, i (n - i)]] + Floor[(i (n - i))/DivisorSigma[0, i (n - i)]]) (1 - Ceiling[i/DivisorSigma[0, i]] + Floor[i/DivisorSigma[0, i]]) (1 - Ceiling[(n - i)/DivisorSigma[0, n - i]] + Floor[(n - i)/DivisorSigma[0, n - i]]), {i, Floor[n/2]}] > 0, n, {}], {n, 150}]]
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|