19227

Appears in sequences

• Numbers k such that the central binomial coefficient C(2k,k) is divisible by k^2.at n=35A121943
• Numbers k such that k and k+1 have 4 distinct prime factors.at n=27A140078
• a(n) = (2*n^3 + 5*n^2 - 3*n)/2.at n=25A162256
• Right edge of triangular table A138612.at n=36A166019
• Number of Carmichael numbers between 2^n and 2^(n+1).at n=47A182490
• Least k such that k(k+1)(k+2)(k+3) is divisible by prime(n)#.at n=8A226891
• Number of (n+1) X (3+1) 0..1 arrays with every 2 X 2 subblock ne-sw antidiagonal difference nondecreasing horizontally and nw+se diagonal sum nondecreasing vertically.at n=9A258549
• a(n) = (n+1)*Sum_{k=0..(n-1)/2} (binomial(k+1,n-2*k-1)*binomial(2*k,k)/(k+1)^2).at n=16A270709
• Numbers k such that k and k+1 each have at least 4 distinct prime factors.at n=27A321504
• Positions of 2 in A309059.at n=12A330160
• Number of finite even-length multisets of positive integers whose right half sums to n.at n=29A360956
• Expansion of (1/x) * Series_Reversion( x * (1-x+x^2)^3 ).at n=8A368971
• Numbers m such that the product m*(m+1) has a set of prime divisors, from greatest down to 2, that is missing exactly two prime divisors.at n=45A391970