2391483

Appears in sequences

• a(n) = (3^n - 3)/2.at n=13A029858
• a(n) = 3*(a(n-2) + 1), with a(0) = 1, a(1) = 3.at n=25A087503
• Expansion of (1+3x)/((1-x^2)(1-3x^2)).at n=25A094025
• a(0) = 1, a(1) = 3, a(n) = 3*a(n-1) + 3 for n > 1.at n=13A123109
• a(n) = 3*A132357(n).at n=12A135264
• Numbers of the form p*q, where p is prime and q=(p^k-1)/(p-1) is also prime for some integer k>1.at n=21A330832
• a(n) is the numerator of the ratio of winning probabilities in a game similar to A370823, but with a draw and single round odds A:B:draw of 3:2:1.at n=12A370825
• Nonprime-powers k such that, for any prime p dividing k and m = 1+floor(log k/log p), rad(p^m (mod k)) divides k, where rad = A007947.at n=30A381750
• Numbers k in A024619 such that all residues r (mod k) in row k of A381801 are such that rad(r) divides k, where rad = A007947.at n=23A382438