219667417263
domain: N
Appears in sequences
- a(n) = 7*3^n.at n=22A005032
- a(n) = n*3^n.at n=21A036290
- a(n) = (2n-1) * 3^(2n-1).at n=10A060851
- a(n) = (7*3^n - 4*0^n)/3.at n=23A082541
- a(n) = 3*a(n-1) for n>2; a(0)=1, a(1)=3, a(2)=7.at n=24A141495
- Egyptian fraction expansion for Pi/4 = arctan(1/2) + arctan(1/3) (Hutton 1776).at n=21A157327
- Least term of A094179 with exactly 2n divisors.at n=22A204046
- Least term of A004767 with exactly 2n divisors.at n=22A204086
- Expansion of g.f. (1-2*x)/(1-9*x).at n=12A270472
- Smallest number having exactly n divisors ending with 3 or 7.at n=22A331082
- a(n) is the least number with exactly n divisors of the form 4*k+3.at n=23A364585