19599

Appears in sequences

• Numbers k such that 227*2^k+1 is prime.at n=15A032490
• Number of not-necessarily-symmetric n X 2 crossword puzzle grids.at n=10A034182
• Squarefree numbers k with largest prime factor = floor(sqrt(k)).at n=24A071311
• Squarefree numbers of the form (prime(k)+1)*(prime(k+1)+1)/4.at n=11A079095
• Values of k such that {s(1),...,s(k)} is a palindrome, where {s(1),s(2),...} is the fixed point of the substitutions 0->1 and 1->110.at n=20A098894
• Expansion of (1+4*x+x^2)/((1-x^2)*(1-2*x-x^2)); a Pellian-related sequence.at n=10A114696
• a(n) = 16n^2 + 32n + 15.at n=34A141759
• a(n) = 784*n - 1.at n=24A158399
• The odd composites c such that c=q*g*j*y/2 and q+g=j*y where q,g,j,y are distinct primes.at n=33A167629
• a(n) = (8*n+3)*(8*n+5).at n=17A177065
• Variation on Fermat's Diophantine m-tuple: 1 + the GCD of any two distinct terms is a square.at n=21A274697
• Least common multiple of 5*n+1 and 5*n-1.at n=28A282285
• Least common multiple of 7*n+1 and 7*n-1.at n=20A282286
• Numbers of the form 16n^2 + 32n + 15 for which the central region of its symmetric representation of sigma consists of two subparts of sizes 4n+7 and 4n+1, n>=0.at n=28A335574
• Products p*q*r of three distinct primes such that (p*q) mod r, (p*r) mod q and (q*r) mod p are all prime.at n=21A338704
• Long leg of the only primitive Pythagorean triple whose inradius is the n-th odd prime and whose short leg is an even number.at n=32A367335
• Least integer k >= 0 such that binomial(k*n,k+1) = -1 mod n, or -1 if no such integer exists.at n=9A383505
• Square array A(n,k), n >= 0, k >= 0, read by antidiagonals downwards, where column k is the expansion of B(x)^k, where B(x) is the g.f. of A384943.at n=42A384946
• Number of Sylow permutations in S_n.at n=8A387061