2191531

Appears in sequences

• (Provable) Sierpiński numbers: odd numbers n such that for all k >= 1 the numbers n*2^k + 1 are composite.at n=19A076336
• Smallest Sierpinski number that is divisible by the n-th prime.at n=25A222534
• Odd integers n such that for every integer k>0, n*2^k+1 has a divisor in the set { 3, 5, 7, 13, 19, 37, 73 }.at n=1A244562
• Odd numbers n not congruent to 5 mod 6 such that for all k >= 1 the numbers n*4^k + 1 are composite.at n=18A251057
• a(1) = 78557 (the first Sierpinski number); thereafter a(n+1) = Od(3*5*7*13*19*37*73 - a(n)), where Od(m) is the odd part of m.at n=2A368560
• a(1) = 78557 (the first Sierpinski number); thereafter a(n+1) = Od(3*5*7*13*19*37*73 - a(n)), where Od(m) is the odd part of m.at n=16A368560