|
| |
|
|
A062407
|
|
Numbers of the form Sum_{j=1..k} sigma(j) that are square.
|
|
2
|
|
|
|
1, 4, 2304, 24964, 73441, 1560001, 132549169, 1626428241, 147805647025, 3518227981636, 120105730444176, 1760865925304929, 1455206977344160000, 23275351872778367961, 17074391403452830178209, 26164085055965187661456, 37159616101199155480921
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,2
|
|
|
COMMENTS
|
|
|
|
LINKS
|
|
|
|
PROG
|
(PARI) for(n=1, 3000, x=sum(k=1, n, sigma(k)); if(issquare(x), print1(x, ", "), ))
(PARI) { n=0; for (m=1, 10^5, x=sum(k=1, m, sigma(k)); if (issquare(x), write("b062407.txt", n++, " ", x); if (n==8, break)) ) } \\ Harry J. Smith, Aug 07 2009
|
|
|
CROSSREFS
|
|
|
|
KEYWORD
|
nonn
|
|
|
AUTHOR
|
|
|
|
EXTENSIONS
|
|
|
|
STATUS
|
approved
|
| |
|
|
