67409

Properties

Appears in sequences

• a(n) = Sum_{k=0..n-2} T(n,k) * T(n,k+2), with T given by A026300.at n=5A026941
• a(n) is smallest prime > 2*a(n-1), a(1) = 13.at n=12A065546
• a(n) = Sum_{k=0..n} (-1)^(n-k)*A000041(k).at n=47A087787
• For a given unrestricted partition pi, let P(pi)=lambda(pi), if mu(pi)=0. If mu(pi)>0 then let P(pi)=nu(pi), where nu(pi) is the number of parts of pi greater than mu(pi), mu(pi) is the number of ones in pi and lambda(pi) is the largest part of pi.at n=46A100818
• Primes p such that p+2, p*(p+2) + 12 and p*(p+2) + 14 are also prime.at n=9A130736
• a(1) = 1, a(n+1) = least prime p > a(n) such that a(n) + p is a square.at n=28A178825
• Number of 2's in the last section of the set of partitions of n.at n=49A182712
• Number of 2's in all partitions of 2n+1 that do not contain 1 as a part.at n=24A182717
• a(n) = b_f(n) where f is the 2-periodic sequence f(k) = (-1)^k (see comments).at n=16A186265
• Number of (n+1)X(5+1) 0..2 arrays with nondecreasing min(x(i,j),x(i,j-1)) in the i direction and nondecreasing absolute value of x(i,j)-x(i-1,j) in the j direction.at n=1A250991
• T(n,k)=Number of (n+1)X(k+1) 0..2 arrays with nondecreasing min(x(i,j),x(i,j-1)) in the i direction and nondecreasing absolute value of x(i,j)-x(i-1,j) in the j direction.at n=16A250994
• Number of (2+1)X(n+1) 0..2 arrays with nondecreasing min(x(i,j),x(i,j-1)) in the i direction and nondecreasing absolute value of x(i,j)-x(i-1,j) in the j direction.at n=4A250996
• Primes which yield again a prime when the digits are taken according to the lexicographically first superpermutation of corresponding order and of minimal length.at n=44A332088
• Primes p such that p+2, p*(p+1)/2-2 and p*(p+1)/2+2 are also primes.at n=22A349336
• Prime numbersat n=6713