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A116012 Numbers k such that k + sigma(k) + sigma(sigma(k)) is a fourth power. 5
19, 1873, 147497, 792736, 4551733, 4967176, 7333813, 8539521, 8674128, 12388853, 12948373, 18331664, 24834369, 36294936, 50952310, 116340016, 170434387, 196966352, 222505713, 236504256, 286766145, 390771936, 426323088, 532998481, 778930925, 805653001 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..26.

EXAMPLE

792736 + sigma(792736) + sigma(sigma(792736)) = 56^4.

PROG

(PARI) for(n=1, 10^9, s=sigma(n); if(ispower(n+s+sigma(s), 4), print(n))) /* Donovan Johnson, Feb 17 2013 */

CROSSREFS

Cf. A116013, A116014, A116015.

Sequence in context: A180394 A220990 A098846 * A203704 A087353 A355982

Adjacent sequences: A116009 A116010 A116011 * A116013 A116014 A116015

KEYWORD

nonn

AUTHOR

Giovanni Resta, Feb 13 2006

EXTENSIONS

a(5)-a(26) from Donovan Johnson, Feb 17 2013

STATUS

approved

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Last modified December 4 20:32 EST 2022. Contains 358570 sequences. (Running on oeis4.)