21460

Appears in sequences

• a(n) = 5*a(n-1) + 4*a(n-2), with a(0) = 4, a(1) = 4.at n=6A106567
• Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0), ending on the vertical axis and consisting of n steps taken from {(-1, -1), (0, -1), (0, 1), (1, -1), (1, 0), (1, 1)}.at n=9A151482
• a(n) = n*A007504(n)/2 = n*(sum of first n primes)/2.at n=29A156778
• a(n) = n^4 + 5*n^2 + 4.at n=12A156798
• Expansion of Product_{k>=1} 1 / ((1 - x^k) * (1 - x^(k^3))).at n=28A369579
• Numbers k such that (3^k + 3*k)/3 is prime.at n=11A370658