34948

Appears in sequences

• a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (natural numbers), t = (primes).at n=44A024867
• a(n) = 5 + floor( Sum_{j=1..n-1} a(j)/3 ).at n=31A120151
• Number of slanted n X 4 (i=1..n) X (j=i..4+i-1) 1..4 arrays with all 1s connected, all 2s connected, all 3s connected, all 4s connected, 1 in the upper left corner, 2 in the upper right corner, 3 in the lower left corner, 4 in the lower right corner, and with no element having more than 3 neighbors with the same value.at n=10A165381
• a(0)=-4; a(n+1) = 2*a(n) + period 4: repeat 6,1,2,5.at n=19A180343
• Number of binary strings of length 2n which contain the reversals of each of their two halves.at n=10A237501
• Number T(n,k) of permutations p of [n] with no fixed points where the maximal displacement of an element equals k; triangle T(n,k), n>=0, 0<=k<=n, read by rows.at n=51A259784
• Number of permutations of [n] with no fixed points where the maximal displacement of an element equals six.at n=3A321052
• a(n) = Sum_{k=0..n} 2^(n-k) * floor(k/4).at n=18A368346
• a(n) is the number of ways to select three distinct points of an n X n grid forming a triangle whose sides do not pass through a grid point.at n=9A372218