217409

Properties

Appears in sequences

• a(1) = 1, a(2) = 1, a(n+1) = 2n*a(n) - a(n-1). Symmetrically a(n) = (a(n-1) + a(n+1))/((n-1) + (n+1)).at n=7A093986
• Numerator of n-th partial sum of the Van der Waerden-Ulam binary measure of the primes.at n=17A127200
• Numbers k such that k, k+1, k+2, k+3 and k+4 are terms of A288041.at n=14A336221
• Prime numbersat n=19400