20557

Appears in sequences

• Strong pseudoprimes to base 72.at n=14A020298
• Numbers k such that the continued fraction for sqrt(k) has period 83.at n=15A020422
• Number of partitions satisfying (cn(0,5) = 0 and cn(1,5) = cn(4,5)).at n=58A036818
• Discriminants of real quadratic fields with class number 2 and related continued fraction period length of 23.at n=18A051988
• Largest eigenvalue, rounded to the nearest integer, of a rank n matrix of 1..n^2 filled successively along antidiagonals (A069480).at n=32A072332
• Ulam's spiral (ENE spoke).at n=36A143856
• Number of binary strings of length n with no substrings equal to 0001 0110 or 1000.at n=14A164477
• Composite numbers coprime to 6 such that A179382(n) = A000265(n-1), the odd part of n-1.at n=32A225913
• Number of ordered triples (i,j,k) with |i|, |j|, |k|, |i*j*k| <= n.at n=38A226359
• Squarefree semiprimes k such that k+1 is the product of three distinct primes and k+2 is the product of four distinct primes.at n=22A376352