40560

Appears in sequences

• a(n) = a(1) + a(2) + ... + a(n-1) + a(m) for n >= 4, where m = n - 1 - 2^p and p is the unique integer such that 2^p < n-1 <= 2^(p+1), with a(1) = 1, a(2) = 3, and a(3) = 4.at n=15A049978
• Number of ways to place 2 nonattacking kings on an n X n board.at n=17A061995
• Numbers k that, when expressed in base 5 and then interpreted in base 8, give a multiple of k.at n=43A062930
• a(n) = 18n^3 + 6n^2.at n=13A087887
• Location of records in A099564.at n=12A099565
• Sum of the square root of n-th square triangular number and n-th Pell (or lambda) number (A000129).at n=6A113449
• G.f.: A(x) = x/(1-x) o x/(1-x^2) o x/(1-x^4) o x/(1-x^8) o..., composition of functions x/(1 - x^{2^n}) for n=0,1,2,3,...at n=19A136752
• If n = p*10^i + q*10^(i-1) + r*10^(i-2) + ... in decimal notation, then a(n) = p!*10^i + q!*10^(i-1) + r!*10^(i-2)+ ... .at n=48A182287
• Areas A of the triangles such that A, the sides and the three altitudes are integers.at n=38A210643
• Number of triples (w,x,y) with all terms in {0,...,n} and w >= floor((x+y)/3).at n=38A212972
• E.g.f. satisfies: A(x) = x - log(1 - A(x)^2).at n=5A213640
• Area A of the cyclic quadrilaterals PQRS with PQ>=QR>=RS>=SP, such that A, the sides, the radius of the circumcircle and the two diagonals are integers.at n=56A219225
• Integer areas A of integer-sided cyclic quadrilaterals such that the length of the circumradius is a perfect square.at n=9A233315
• Number of partitions of n into 10 parts such that every i-th smallest part (counted with multiplicity) is different from i.at n=18A244246
• Number of set partitions of [n] such that i-j is a multiple of three for all i,j belonging to the same block.at n=14A275070
• G.f. A(x) satisfies: 1 = ...(((((A(x) - x) - x^2)^(1/2) - x^3)^(1/3) - x^4)^(1/4) - x^5)^(1/5) -...- x^n)^(1/n) -..., an infinite series of nested n-th roots.at n=9A275753
• a(n) is the number of permutations of length n that avoid the pattern 321 and the mesh pattern (12, 189) or the same sequence for the mesh patterns (12, 243), (12, 378), (12, 414).at n=11A289595
• a(n) = 8*7*6*5*4*3*2*1 + 16*15*14*12*11*10*9 + ... + (up to the n-th term).at n=9A319872
• Triangular array read by rows. T(n,k) is the number of labeled transitive relations on [n] that have exactly k symmetric points.at n=25A355783
• Number of integer compositions of n whose leaders of strictly decreasing runs are weakly increasing.at n=21A374764