A221263 Numbers k such that sigma(k) is the fifth power of the sum of the prime divisors of k.

213556659624, 359544809085, 1329797339640, 1548635130140, 1746049287480, 1810001934510, 1867318744632, 1875874796664, 1909975290390, 2040256862622, 2516452216712, 3407803953785, 6329875033944, 7792308679512, 7840198408728, 7877108796312, 8098434291288, 8241610823832

Offset

1,1

Comments

The smallest k for which sigma(k) = sopf(k)^6 is 45770980141656. Other such values are 5245619666623908 and 5582294774581035.

Links

Robert Gerbicz, Table of n, a(n) for n = 1..10000

Example

213556659624 = 2^3*3^3*7^3*11*31*79*107 and sigma(213556659624) = (2+3+7+11+31+79+107)^5.

Crossrefs

Cf. A000203, A008472.

Cf. A187771 (sigma(k)=sopf(k)^3), A221262 (sigma(k)=sopf(k)^4).

Sequence in context: A108048 A108496 A185430 * A172614 A112431 A202725

Adjacent sequences: A221260 A221261 A221262 * A221264 A221265 A221266

Keyword

nonn

Author

Giovanni Resta, Jan 07 2013

Status

approved