A064501 Sum of unitary divisors of n^3 is a square.

1, 2, 345, 690, 46035, 92070, 29764712, 46059025, 52096527, 61565160, 92118050, 94399912, 104193054, 140553735, 155064548, 184566592, 188194335, 215515727, 281107470, 288564647, 376388670, 431031454, 479685360, 577129294, 735517552, 888105120, 1066525860

Offset

1,2

Links

Donovan Johnson, Table of n, a(n) for n = 1..50 (terms < 10^11)

Prog

(PARI) {usigma(n, s=1, fac, i)= fac=factor(n); for(i=1, matsize(fac)[1], s=s*(1+fac[i, 1]^fac[i, 2]); ); return(s); } for(n=1, 10^6, if(issquare(usigma(n^3)), print1(n, " ")))

Crossrefs

Cf. A034448.

Sequence in context: A063968 A172136 A248172 * A063831 A216356 A064023

Adjacent sequences: A064498 A064499 A064500 * A064502 A064503 A064504

Keyword

nonn

Author

Jason Earls, Oct 05 2001

Extensions

More terms from Naohiro Nomoto, Oct 22 2001

a(8)-a(27) from Donovan Johnson, Jul 15 2012

Status

approved