A057231 Numbers k such that k divides 9^k + 8^k + 7^k.

1, 2, 3, 9, 27, 33, 81, 194, 243, 729, 1647, 2187, 2673, 6561, 15957, 19683, 59049, 133407, 177147, 216513, 314523, 531441, 699597, 1306833, 1594323, 4782969, 5622777, 5640273, 6762933, 10805967, 11708163, 14348907, 17537553, 20069451, 32537457, 43046721, 66075831

Offset

1,2

Links

Table of n, a(n) for n=1..37.

Maple

select(t -> (9 &^ t + 8 &^ t + 7 &^ t) mod t = 0, [$1..10^7]); # Robert Israel, Jan 29 2020

Mathematica

Select[ Range[ 10^6 ], Mod[ PowerMod[ 9, #, # ] + PowerMod[ 8, #, # ] + PowerMod[ 7, #, # ], # ] == 0 & ]

Crossrefs

Supersequence of A000244.

Cf. A074580.

Sequence in context: A380629 A309814 A177928 * A178028 A045596 A057299

Adjacent sequences: A057228 A057229 A057230 * A057232 A057233 A057234

Keyword

nonn

Author

Robert G. Wilson v, Sep 20 2000

Extensions

a(24)-a(29) from Robert Israel, Jan 29 2020

More terms from Jinyuan Wang, Apr 15 2020

Status

approved