33619

Properties

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 = (Fibonacci numbers), t = (primes).at n=25A025088
• Primes p having exactly one partition into distinct divisors of p+1.at n=42A085499
• Lesser prime factor of semiprimes in A089539.at n=28A089540
• a(n) = 20*n^2 - 1.at n=40A158491
• Primes p of the form 4m+3 for which there are exactly as many primitive roots modulo p in the interval [0,p/2] as in the interval [p/2,p].at n=29A172490
• Primes of the form 5n^2 - 1.at n=22A201783
• G.f. A(x) satisfies: A(x - x^2 - x^2*A(x)) = x.at n=8A295539
• Number of integer partitions of n that can be partitioned into two or more blocks with equal sums.at n=40A321452
• a(n) = Sum_{k=1..n} mu(gcd(n, k)) * lcm(n, k) / gcd(n, k).at n=40A332658
• Discriminants of imaginary quadratic fields with class number 35 (negated).at n=37A351673
• Numbers k such that A073734(k) is neither squarefree nor a prime power.at n=12A365899
• Prime numbersat n=3602