18994

Appears in sequences

• Coordination sequence for MgNi2, Position Ni3.at n=34A009934
• Expansion of 1/((1-x)^2*Product_{k>=1} (1-x^k)).at n=22A014153
• Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 18.at n=9A031606
• a(0) = 0, a(1) = 1 and for n >= 2, a(n) = floor(2 * sqrt(a(n-2) * a(n-1))).at n=24A093333
• G.f.: exp( Sum_{n>=1} 2^A090740(n) * x^n/n ) where A090740(n) = highest exponent of 2 in 3^n-1.at n=25A182000
• Number of 0..n arrays x(0..3) of 4 elements with zero 3rd differences.at n=38A200155
• Number of partitions of n such that m(2) < m(3), where m = multiplicity.at n=43A240063
• Number of partitions of n such that neither the number of parts nor the number of distinct parts is a part.at n=40A241380
• Numbers of the form 7^x + y^7 with x, y >= 0.at n=28A250715
• Composite numbers k such that phi(x) = psi(k)*phi(k) has no solution.at n=13A292714
• Number of nX3 0..1 arrays with every element equal to 1, 3, 4, 5 or 6 king-move adjacent elements, with upper left element zero.at n=10A298449
• Numbers k such that k^2+1, (k+2)^2+1 and (k+6)^2+1 are prime.at n=30A302021