53131
domain: N
Appears in sequences
- Strong pseudoprimes to base 9.at n=38A020235
- Strong pseudoprimes to base 22.at n=18A020248
- Strong pseudoprimes to base 75.at n=33A020301
- a(n) = a(n-1) + a(n-2) + 2 where a(0) = a(1) = 1.at n=21A111314
- Diagonal sums of the triangle A132047.at n=21A144707
- Odd composite squarefree numbers k such that r = 2*(p - 2 + k/p)/(p-1) is an integer for each prime divisor p of k.at n=34A180248
- G.f. satisfies: A(x) = 1 + x*A(x/A(-x)).at n=11A211768
- "Strong impostors" not divisible by 4: Those numbers s !== 0 (mod 4) such that lambda(s) | 2(s-1), where lambda is the Carmichael function (A002322).at n=39A318555
- a(n) = binomial(n + 4, n - 1) + 1.at n=21A323228