41528

Appears in sequences

• All 81 combinations of prefixing and following a(n) by a single digit are nonprime.at n=31A032734
• a(n) cannot be prefixed or followed by any digit to form a prime ('empty' prefixes allowed).at n=9A032736
• Composite numbers k such that all the decimal concatenations ik and ikj (i, j = 1...9) are also composite.at n=21A032737
• a(n) cannot be prefixed or followed by any digit to form a prime ('empty' prefixes and suffixes are allowed).at n=7A032738
• G.f. satisfies A(x) = 1 + x*A(x)*A(x^2)*A(x^3)*...*A(x^n)*...at n=18A091865
• a(n) = ceiling(A013984(n)/2).at n=27A173697
• The Wiener index of the double-comb graph \/_\/_\/...\/_\/ with 3n (n>=1) nodes. The Wiener index of a connected graph is the sum of the distances between all unordered pairs of vertices in the graph.at n=28A192025
• Number of rooted planar binary unlabeled trees with n leaves and caterpillar index >= 4.at n=12A214201
• Numbers k such that k divides 1 + Sum_{j=1..k} prime(j)^14.at n=38A232966
• Number of nX3 0..1 arrays with every element equal to 1, 2, 3, 4, 5 or 8 king-move adjacent elements, with upper left element zero.at n=5A299368
• Number of nX6 0..1 arrays with every element equal to 1, 2, 3, 4, 5 or 8 king-move adjacent elements, with upper left element zero.at n=2A299371
• T(n,k)=Number of nXk 0..1 arrays with every element equal to 1, 2, 3, 4, 5 or 8 king-move adjacent elements, with upper left element zero.at n=30A299373
• T(n,k)=Number of nXk 0..1 arrays with every element equal to 1, 2, 3, 4, 5 or 8 king-move adjacent elements, with upper left element zero.at n=33A299373
• Irregular table read by rows: T(n,k) is the number of k-gons, k>=2, among all distinct circles that can be constructed from a point on the origin and n equally spaced points on each of the +x,-x,+y,-y coordinates axes when each pair of points is connected by a circle and where the points lie at the ends of the circles' diameter.at n=43A362236