1,2
a(15) > 2*10^21. - Donovan Johnson, Feb 17 2010
Table of n, a(n) for n=1..14.
(PARI) for(n=1, 3000, x=sum(k=1, n, sigma(k)); if(issquare(x), print(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
Cf. A024916.
Sequence in context: A172941 A180993 A192889 * A212799 A097476 A047676
Adjacent sequences: A062404 A062405 A062406 * A062408 A062409 A062410
nonn
Jason Earls, Jul 08 2001
Terms a(7) and a(8) added by Harry J. Smith, Aug 07 2009
a(9)-a(14) from Donovan Johnson, Feb 17 2010
approved
