31351

Appears in sequences

• a(n) = a(n-1) + a(m) for n >= 4, where m = 2*n - 2 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = a(2) = 1 and a(3) = 3.at n=42A050035
• The array in A059219 read by antidiagonals in 'up' direction.at n=50A059220
• The array in A059219 read by antidiagonals in the direction in which it was constructed.at n=50A059235
• Numbers n such that sigma_3(n) is divisible by square of cototient of n, while n is not a prime number.at n=17A091286
• Number of (n+3) X 9 0..2 matrices with each 4 X 4 subblock idempotent.at n=11A224726
• a(n) is the least k such that A033273(k) is equal to (A033273(n*k + 1) - 1)/n where A033273(n) is the number of nonprime divisors of n.at n=23A352256