18310546875
domain: N
Appears in sequences
- Expansion of g.f. (1 - 2*x)/(1 - 5*x).at n=15A005053
- a(n) = 5^(n/2) for n even, a(n) = 3*5^((n-1)/2) for n odd.at n=29A056487
- Reciprocal of n terminates with an infinite repetition of digit 3. Multiples of 10 are omitted.at n=23A064562
- a(n) = (4*5^n + (-5)^n)/5.at n=15A083222
- Expansion of (1 + 3x - 2x^2 - 12x^3)/(1 - 9x^2 + 20x^4).at n=29A097111
- a(1) = 1, a(2) = 3; for n >= 3, take a(n) to be the smallest odd number not occurring earlier such that a(n-1) divides the concatenation a(n-2)a(n).at n=29A111386
- a(n) = 5*a(n-2) for n > 2; a(1) = 3, a(2) = 5.at n=28A163114
- Hypotenuses for which there exist exactly 14 distinct integer triangles.at n=2A290502