21053

Appears in sequences

• Denominators of continued fraction convergents to sqrt(861).at n=10A042663
• Discriminants of real quadratic fields with class number 2 and related continued fraction period length of 13.at n=27A051978
• Number of meaningful differential operations of the n-th order on the space R^9.at n=12A090994
• a(1) = 1; thereafter a(n) is always the smallest integer > a(n-1) not leading to a contradiction, such that any five consecutive digits in the sequence sum up to a prime.at n=33A152605
• Molecular topological indices of the pan graphs.at n=33A192836
• Number of points of norm <= n in the bi-truncated cubic honeycomb (3-dimensional lattice, with truncated-octahedral cells).at n=17A276450
• Maximum k such that there are k nonisomorphic n-vertex trees with the same degree sequence.at n=19A295637
• Number of nX2 0..1 arrays with every element unequal to 1, 2, 3 or 5 king-move adjacent elements, with upper left element zero.at n=9A304013
• T(n,k)=Number of nXk 0..1 arrays with every element unequal to 1, 2, 3 or 5 king-move adjacent elements, with upper left element zero.at n=56A304019
• T(n,k)=Number of nXk 0..1 arrays with every element unequal to 1, 2, 3, 5 or 8 king-move adjacent elements, with upper left element zero.at n=56A305367
• Composite hypotenuses of primitive Pythagorean triangles (A120961) that are not circumdiameters of non-Pythagorean primitive Heronian triangles (A285579).at n=28A329148