OFFSET
1,1
REFERENCES
J. Y. Lee and J.-L. Kim, Powers, Pythagorean triples, and Fermat's Last Theorem in carryless arithmetic mod 10, preprint, April, 18, 2013.
LINKS
Jon-Lark Kim, Preprints
Index entries for linear recurrences with constant coefficients, signature (12,-20).
FORMULA
a(k) = (1/4)*{9* 10^(k-1) - 2^(k-1)} + 2^(k-1).
a(n) = 12*a(n-1)-20*a(n-2). G.f.: -3*x*(4*x-1) / ((2*x-1)*(10*x-1)). - Colin Barker, May 11 2013
EXAMPLE
For k=1, there are three one-digit 4th powers: 1^4=9^4=3^4=7^4=1, 2^4=8^4=4^4=6^4=6, 5^4=5.
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Jon-Lark Kim, Apr 28 2013
EXTENSIONS
More terms from Colin Barker, May 11 2013
STATUS
approved