A016087 First nontrivial or multidigital Armstrong number to base n.

5, 28, 13, 99, 10, 20, 41, 153, 61, 29, 17, 244, 113, 342, 40, 80, 181, 2413, 26, 97, 53, 11080, 313, 5425, 90, 180, 421, 68, 37, 205, 109, 356, 613, 5489, 160, 85, 761, 10413, 261, 353, 50, 637, 1013, 292, 104, 500, 1201, 1025, 1301, 541, 281, 127295, 178

Offset

3,1

Comments

Also called narcissistic numbers or pluperfect digital invariants.

a(90) > 10^8 if it exists at all. - Robert Israel, Aug 24 2015

Links

Tim Johannes Ohrtmann, Table of n, a(n) for n = 3..89

Robert Israel, Known values of n, a(n) for n = 3..269 (n=90 still unknown)

Dik T. Winter, Armstrong numbers

Maple

f:= proc(n) local k, L, m;
  for k from n+1 do
    L:= convert(k, base, n);
    m:= nops(L);
    if add(t^m, t=L) = k then return(k) fi
  od
end proc:
map(f, [$3..89]); # Robert Israel, Aug 24 2015

Mathematica

Do[k = n + 1; While[l = IntegerDigits[k, n]; Apply[ Plus, l^Length[l]] != k, k++ ]; Print[k], {n, 3, 75} ]

Crossrefs

Cf. A005188, A259347.

Sequence in context: A000878 A052470 A351749 * A347251 A321236 A351774

Adjacent sequences: A016084 A016085 A016086 * A016088 A016089 A016090

Keyword

nonn,base

Author

Robert G. Wilson v

Extensions

Edited and extended by Robert G. Wilson v, Feb 28 2002

Status

approved