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A067791
Smallest multidigit prime such that the sum of the squares of its digits is equal to n times the product of its digits, or 0 if no such prime exists.
1
11353, 11, 211, 1111116211, 11411, 511111, 1111111111111111111111111111213, 11111117, 111111181, 1111111111111111111711, 2111111111111111111, 111111111111111121111, 1111111111111111111111141111111111111, 1111111111111111211111111
OFFSET
1,1
COMMENTS
Sum(xi^2) = n*Product(xi) where xi is the i-th digit of a prime in base 10. The zero has been entered for those n values such that no solution has been found up to 10^7.
No more terms up to 4.4*10^11.
a(n) > (10^52-1)/9 for n = 18, 20, and 22. - Donovan Johnson
LINKS
Sean A. Irvine, Java program (github)
CROSSREFS
Sequence in context: A266181 A179917 A287245 * A067779 A202377 A210122
KEYWORD
nonn,base
AUTHOR
Felice Russo, Feb 06 2002
EXTENSIONS
a(8) and a(9) corrected by Charles R Greathouse IV, Nov 19 2010
a(4), a(7), a(10)-a(17), a(19), a(21) and a(23) from Donovan Johnson, Nov 20 2010
STATUS
approved