344175

Appears in sequences

• a(n)= 5*(n-1)*a(n-1) -(n-1)*a(n-2), with a(0)=0, a(1)=1.at n=6A108207
• Number of (n+1) X (n+1) -2..2 symmetric matrices with every 2 X 2 subblock having sum zero and one, two or three distinct values.at n=12A211116
• Composite numbers n such that the sum of proper divisors of n divides 2^n+1.at n=31A278337