

A153874


Numbers n = abc...k such that a^2*b^2*c^2*...k^2  1 = n.


0




OFFSET

1,1


LINKS

Table of n, a(n) for n=1..3.


EXAMPLE

1) 143 = 1^2 * 4^2 * 3^2  1 = 1 * 16* 9  1. 2) 323 = 3^2 * 2^2 * 3^2  1 = 9 * 4 * 9  1. 3) 1663 = 1^2 * 1^2* 6^2 * 6^2 * 3^2  1 = 1 * 1 * 36 * 36 * 9  1.


PROG

(PARI) n=1; while(n!=10^16, n+=1; j=n^21; k=1; while(j!=0, k=k*(j%10)^2; j=floor(j/10)); if(k1==n^21, print(n^21)))


CROSSREFS

Sequence in context: A176876 A257767 A158136 * A003902 A261074 A213337
Adjacent sequences: A153871 A153872 A153873 * A153875 A153876 A153877


KEYWORD

base,nonn,fini,full,bref


AUTHOR

Vikram Pandya, Jan 03 2009


EXTENSIONS

Edited by N. J. A. Sloane, Jan 03 2009


STATUS

approved



