A114068 sigma(n) + phi(n) is a fourth power.

110, 125, 609, 2047, 4895, 9819, 10149, 10367, 18974, 31269, 37032, 40662, 42032, 44238, 44835, 48125, 51459, 51535, 52487, 77425, 90090, 116633, 129846, 137865, 145299, 146566, 151438, 159565, 161614, 162334, 207710, 307327, 357116

Offset

1,1

Links

Donovan Johnson, Table of n, a(n) for n = 1..1000

Example

sigma(110) + phi(110) = 256 = 4^4.

Prog

(PARI) isok(n) = ispower(sigma(n) + eulerphi(n), 4); \\ Michel Marcus, Jan 09 2014

Crossrefs

Cf. A065387, subsequence of A062784.

Sequence in context: A274944 A275343 A059469 * A073494 A073488 A244389

Adjacent sequences: A114065 A114066 A114067 * A114069 A114070 A114071

Keyword

nonn

Author

Giovanni Resta, Feb 13 2006

Status

approved