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A364601 Numbers m such that, if k is the number of digits of m, then for some r > 1, the sum of the k-th powers of the digits of m^r is equal to m. 0
1, 7, 8, 9, 180, 205, 38998, 45994, 89080, 726191, 5540343, 7491889, 8690141, 167535050, 749387107, 9945245922 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Corresponding r's: any, 4, 3, 2, 6, 2, 2, 2, 2, 2, 3, 2, 3, 3, 4, 3.
LINKS
René-Louis Clerc, The Perfect R-Narcissistic Numbers, 2023.
René-Louis Clerc, Perfect r-narcissistic numbers in any base, hal-04376934, 2024.
René-Louis Clerc, Nombres S+P, maxSP, minSP et |P-S|, hal-04507547 [math.nt], 2024. (In French)
EXAMPLE
180 with r=6 satisfies: 180^6 = 34012224000000, 3^3 + 4^3 + 1 + 2^3 + 2^3 + 2^3 + 4^3 = 180.
PROG
(PARI) SomP(n, p)={resu=0; for(i=1, #digits(n), resu+=(digits(n)[i])^p); resu}
Ppdi(k, r)={for(n=10^(k-1), 10^k, if(SomP(n^r, k)==n, print1(n, "; ")))}
CROSSREFS
Cf. A005188 (Armstrong's numbers, case r=1 in our terminology).
Cf. A066003, A066004, A065999 (for terms 7, 8 and 9).
Sequence in context: A048009 A048046 A048092 * A337468 A105860 A096677
KEYWORD
nonn,base,fini,more
AUTHOR
René-Louis Clerc, Jul 29 2023
STATUS
approved

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Last modified April 22 01:34 EDT 2024. Contains 371887 sequences. (Running on oeis4.)