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A051423 Sum of prime divisors of n is congruent to 2^n (mod n). 1
15, 77, 99, 240, 354, 18870, 284481, 302174, 433197, 440973, 453086, 2446619, 5776855, 9961111, 17986255, 19091527, 28997648, 37443680, 40074848, 47602448, 67166528, 129389763, 141963648, 146259296, 152062688, 202038871, 203444576 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Prime factors counted with multiplicity. - Harvey P. Dale, Jul 25 2013

LINKS

Giovanni Resta, Table of n, a(n) for n = 1..88 (terms < 10^11)

EXAMPLE

E.g. 15 = 3*5 and 2^15 = 3+5 (mod 15)

MATHEMATICA

Select[Range[2500000], Total[Flatten[Table[#[[1]], {#[[2]]}]&/@ FactorInteger [#]]] ==PowerMod[2, #, #]&] (* Harvey P. Dale, Jul 25 2013 *)

CROSSREFS

Sequence in context: A041430 A156941 A205440 * A205609 A257925 A205433

Adjacent sequences:  A051420 A051421 A051422 * A051424 A051425 A051426

KEYWORD

nonn,easy,nice

AUTHOR

Joe K. Crump (joecr(AT)carolina.rr.com)

STATUS

approved

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Last modified December 2 23:22 EST 2021. Contains 349445 sequences. (Running on oeis4.)