20017

Appears in sequences

• Pseudoprimes to base 6.at n=39A005937
• Pseudoprimes to base 15.at n=29A020143
• Pseudoprimes to base 90.at n=32A020218
• Strong pseudoprimes to base 6.at n=10A020232
• Strong pseudoprimes to base 36.at n=21A020262
• Strong pseudoprimes to base 52.at n=15A020278
• Numbers k such that the continued fraction for sqrt(k) has period 91.at n=12A020430
• Indices of primes in sequence defined by A(0) = 87, A(n) = 10*A(n-1) - 13 for n > 0.at n=4A101072
• Expansion of (3-2*x-3*x^2)/(1-x-x^2-x^3).at n=17A141523
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, 0, -1), (-1, 1, 1), (0, -1, 0), (1, 1, 0)}.at n=9A149131
• Euler pseudoprimes to base 6: composite integers such that abs(6^((n - 1)/2)) == 1 mod n.at n=25A262053
• Expansion of Product_{k>=1} 1/(1 - x^(k*(k+1)/2))^2.at n=40A298435
• Starts of runs of 3 consecutive numbers with the same total binary weight of their divisors (A093653).at n=14A338453
• 32-gonal numbers: a(n) = n*(15*n-14).at n=37A360436