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A005188 Armstrong (or Plus Perfect, or narcissistic) numbers: n-digit numbers equal to sum of n-th powers of their digits (a finite sequence, the last term being 115132219018763992565095597973971522401).
(Formerly M0488)
+0
30
1, 2, 3, 4, 5, 6, 7, 8, 9, 153, 370, 371, 407, 1634, 8208, 9474, 54748, 92727, 93084, 548834, 1741725, 4210818, 9800817, 9926315, 24678050, 24678051, 88593477, 146511208, 472335975, 534494836, 912985153, 4679307774, 32164049650, 32164049651 (list; graph; listen)
OFFSET

1,2

COMMENT

Let n = d_1 d_2 ... d_k in base 10; then n = Sum_{i=1..k} d_i^k.

REFERENCES

Lionel E. Deimel, Jr. and Michael T. Jones, Finding Pluperfect Digital Invariants: Techniques, Results and Observations, J. Rec. Math., 14 (1981), 87-108.

J. P. Lamoitier, Fifty Basic Exercises. SYBEX Inc., 1981.

Tomas Antonio Mendes Oliveira e Silva (tos(AT)ci.ua.pt) gave the full sequence in a posting (Article 42889) to sci.math on May 09 1994.

Joe Roberts, "The Lure of the Integers", page 35.

Clifford A. Pickover, A Passion for Mathematics, Wiley, 2005; see p. 68.

LINKS

T. D. Noe, Table of n, a(n) for n=1..88 (from Winter)

Anonymous, Narcissistic number

L. E. Deimel, Narcissistic Numbers

H. Heinz, Narcissistic Numbers

W. Lopez, PlanetMath.Org, Armstrong number

W. Schneider, Perfect Digital Invariants: Pluperfect Digital Invariants(PPDIs)

B. Shader, Armstrong number

Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics (1).

Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics (2).

Wikipedia, Narcissistic number

D. T. Winter, Table of Armstrong Numbers

EXAMPLE

153 = 1^3 + 5^3 + 3^3, 4210818 = 4^7 + 2^7 + 1^7 + 0^7 + 8^7 + 1^7 + 8^7.

MATHEMATICA

f[n_] := Plus @@ (IntegerDigits[n]^Floor[ Log[10, n] + 1]); Select[ Range[10^7], f[ # ] == # &] (from Robert G. Wilson v (rgwv(AT)rgwv.com), May 04 2005)

CROSSREFS

Cf. A001694, A007532, A005934, A003321, A014576, A046074.

Similar to but different from A023052.

Sequence in context: A001104 A032561 A023052 this_sequence A032569 A039723 A002998

Adjacent sequences: A005185 A005186 A005187 this_sequence A005189 A005190 A005191

KEYWORD

nonn,base,fini,nice

AUTHOR

njas, Robert G. Wilson v (rgwv(AT)rgwv.com)

EXTENSIONS

32164049651 from Amit Munje (amit.munje(AT)gmail.com), Oct 07 2006

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Last modified July 24 12:00 EDT 2008. Contains 142294 sequences.


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