OFFSET
1,6
COMMENTS
Equivalently, this counts strings of numbers of length n that start with a 1 and which yield a multiple of 3 when read in any base.
LINKS
Peter Kagey, Table of n, a(n) for n = 1..1000
FORMULA
EXAMPLE
For n = 7, the a(7) = 6 (0,1)-polynomials of degree seven such that f(0) = f(1) = f(2) = 0 (mod 3) are
x^7 + x^5 + x^3,
x^7 + x^6 + x^5 + x^4 + x^3 + x^2,
x^7 + x^5 + x,
x^7 + x^3 + x,
x^7 + x^6 + x^5 + x^4 + x^2 + x, and
x^7 + x^6 + x^4 + x^3 + x^2 + x.
CROSSREFS
KEYWORD
nonn
AUTHOR
Peter Kagey, Nov 13 2019
STATUS
approved