1333333333
domain: N
Appears in sequences
- Number of Fibonacci numbers F(k), k <= 10^n, which end in 9.at n=9A073556
- Expansion of g.f. (1+2*x)/((1-x)*(1-10*x)).at n=9A097166
- a(n) = Sum_{k=0..n} C(floor((n+1)/2),floor((k+1)/2)) * 3^k.at n=18A097169
- Smallest semiprime containing exactly n 3's.at n=8A104685
- Smallest semiprime ending in exactly n 3's.at n=8A106658
- Numbers k such that the k-th triangular number contains only digits {1,8,9}.at n=20A119151
- a(n) = A133195(n)/3.at n=28A133201
- Mersenne primes written in base 4.at n=6A161677