18001

Appears in sequences

• Pseudo-squares: a(n) = the least nonsquare positive integer which is 1 mod 8 and is a (nonzero) quadratic residue modulo the first n odd primes.at n=6A002189
• Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 94 ones.at n=13A031862
• Number of primitive (aperiodic) palindromic structures using a maximum of five different symbols.at n=17A056479
• Number of primitive (period n) periodic palindromic structures using a maximum of five different symbols.at n=17A056516
• Odd numbers n for which 19 is the smallest i (>= 1) with Jacobi symbol J(i,n) getting either a value 0 or -1.at n=9A112078
• a(n) = 1 + n^4 + n^6 + n^9 + n^10 + n^14.at n=1A123659
• a(n) = 900*n + 1.at n=19A158407
• a(n) = 20*n^2 + 1.at n=30A158493
• a(n) = 80*n^2 + 1.at n=15A158776
• Number of nX2 1..2 arrays with every element value z a city block distance of exactly z from another element value z.at n=8A209604
• T(n,k)=Number of nXk 1..2 arrays with every element value z a city block distance of exactly z from another element value z.at n=46A209610
• Semiprimes of the form 5*n^2 + 1.at n=19A212707
• Number of n X 3 arrays of the minimum value of corresponding elements and their horizontal, vertical, diagonal or antidiagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and columns, 0..1 n X 3 array.at n=26A219349
• A239461(n) / n^2.at n=17A239464
• n^3 + 4*n^2 - 5*n + 1.at n=25A241577
• Row sums of the triangular array A246696.at n=32A246697
• Square array read by ascending antidiagonals, T(n, k) = k!*[x^k](exp(x)*sum(j=0..n, C(2*n,j)*x^j)), n>=0, k>=0.at n=59A253670
• Smallest nonsquare congruent to a square (mod k^2) for all k = 1..n.at n=16A260709
• Smallest nonsquare congruent to a square (mod k^2) for all k = 1..n.at n=17A260709
• Expansion of (1-q)^k/Product_{j=1..k} (1-q^j) for k=16.at n=14A275644