20609

Appears in sequences

• Numbers k such that the continued fraction for sqrt(k) has period 73.at n=14A020412
• Denominators of continued fraction convergents to sqrt(602).at n=10A042155
• Concatenation of first n terms of A100769 divided by n.at n=5A100770
• a(n) = a(n-1) + 2*a(n-2) - 2*a(n-3) + a(n-5).at n=21A116157
• Minimum value unattainable as the sum of 3 attained values of a*b*c with a,b,c 0..n integers.at n=20A225265
• Number of n X 3 0,1 arrays indicating 2 X 2 subblocks of some larger (n+1) X 4 binary array having a sum of one or less, with rows and columns of the latter in lexicographically nondecreasing order.at n=8A227162
• Number of nX4 0..3 arrays with no element equal to one plus the sum of elements to its left or zero plus the sum of elements above it or zero plus the sum of the elements diagonally to its northwest or zero plus the sum of the elements antidiagonally to its northeast, modulo 4.at n=8A240758
• a(n) is the smallest number whose Collatz ('3x+1') trajectory crosses its initial value exactly n times.at n=53A301937
• Composite hypotenuses of primitive Pythagorean triangles (A120961) that are not circumdiameters of non-Pythagorean primitive Heronian triangles (A285579).at n=25A329148