22504

Appears in sequences

• a(n) = 1*t(n) + 2*t(n-1) + ...+ k*t(n+1-k), where k=floor((n+1)/2) and t is A001950 (upper Wythoff sequence).at n=45A023867
• s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (natural numbers), t = A001950 (upper Wythoff sequence).at n=44A024864
• Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 75.at n=32A031573
• Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 75.at n=1A031753
• Super-4 Numbers (4 * n^4 contains substring '4444' in its decimal expansion).at n=18A032744
• a(n) = (5/6)*n^3+(5/2)*n^2+(8/3)*n.at n=29A092185
• Number of line segments connecting exactly 8 points in an n x n grid of points.at n=42A177724
• Number of (n+2) X 7 0..1 matrices with each 3 X 3 subblock idempotent.at n=15A224556
• Integers m of the form m = 3*p + 5*q = 5*r + 7*s where {p,q} and {r,s} are pairs of consecutive primes.at n=9A283392
• Sum of the squarefree parts of the partitions of n into 4 parts.at n=47A309479
• a(1) = 1; a(n > 1) = Sum_{0 < k < n} (-1)^(n - k - 1) a(n - k) Sum_{d|k} a(d).at n=28A317853
• Number of labeled simple connected graphs with n vertices whose bridges are all leaves, meaning at least one end of any bridge is an endpoint of the graph.at n=6A322395
• Numbers m such that sigma(m)*tau(m) is a square but sigma(m)/tau(m) is not an integer.at n=7A327831
• Expansion of Sum_{k>=0} k * x^k/(1 + k^2 * x).at n=8A349859
• a(n) = Sum_{k = 0..n} ( binomial(n+k-1,k) + binomial(n+k-1,k)^2 ).at n=5A357671