A256361 Numbers that are multiple-digit narcissistic numbers in exactly two bases.

17, 28, 29, 45, 50, 85, 126, 133, 136, 145, 153, 160, 200, 245, 250, 260, 261, 265, 353, 365, 371, 405, 425, 442, 450, 490, 514, 520, 533, 585, 605, 650, 666, 680, 738, 800, 855, 925, 936, 1000, 1025, 1105, 1225, 1233, 1250, 1280

Offset: 1

Author

Tim Johannes Ohrtmann, Mar 26 2015

Keywords

• nonn
• base

Examples

			a(1) = 17 because this is the first number that is a multiple-digit narcissistic number in exactly two bases (3 and 13).
		

Links

• Tim Johannes Ohrtmann, Table of n, a(n) for n = 1..3541
• W. Schneider, Perfect Digital Invariants: Pluperfect Digital Invariants(PPDIs)
• Eric Weisstein's World of Mathematics, Narcissistic Number
• Wikipedia, Narcissistic number

Crossrefs

Cf. A005188.

Cf. A256359 (every number of bases).

Cf. A256360, A256362, A256363, A256364, A256365 (1, 3 to 6 bases).

Cf. A256459 (first occurrences).

Programs

PARI

for(n=3, 1000000, k=0; for(z=2, n, y=n; j=0; L=List(); until(y==0, x=y%z; j++; listinsert(L, x, j); while(!((y%z)==0), y--); y=y/z); t=0; for(p=1, j, t+=L[p]^j); if(n==t, k++)); if(k==2, print1(n, ", ")))