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A153874 Numbers n = abc...k such that a^2*b^2*c^2*...k^2 - 1 = n. 0
143, 323, 11663 (list; graph; refs; listen; history; text; internal format)
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^2-1; k=1; while(j!=0, k=k*(j%10)^2; j=floor(j/10)); if(k-1==n^2-1, print(n^2-1)))

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

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Last modified March 24 07:54 EDT 2017. Contains 283985 sequences.