21410

Appears in sequences

• Numbers k such that sigma(k+2) = sigma(k).at n=27A007373
• Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted then there are a pair of central terms both equal to 9.at n=33A031422
• a(0)=4, a(1)=0, a(2)=0, a(3)=3; thereafter a(n) = a(n-3) + a(n-4).at n=50A050443
• Pseudo-random numbers: gcc 2.6.3 version for 32-bit integers.at n=37A084276
• Positions of sevens (ground states) in A084451.at n=24A084449
• a(n) = C(2n-1,n-1) mod n^3.at n=35A099907
• Numbers m such that A132575(m) = m.at n=18A132579
• Indices n such that A134204(n) < n.at n=29A133242
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, 0, 1), (0, 1, 0), (1, -1, 1), (1, 0, -1)}.at n=10A148335
• Number of n X 2 0,1 arrays indicating 2 X 2 subblocks of some larger (n+1) X 3 binary array having nonzero determinant, with rows and columns of the latter in lexicographically nondecreasing order.at n=14A227554
• Number of (n+1)X(2+1) 0..3 arrays with the maximum plus the upper median minus the minimum of every 2X2 subblock differing from its horizontal and vertical neighbors by exactly one.at n=1A237900
• T(n,k)=Number of (n+1)X(k+1) 0..3 arrays with the maximum plus the upper median minus the minimum of every 2X2 subblock differing from its horizontal and vertical neighbors by exactly one.at n=4A237904
• a(n) = binomial(2*c-1, c-1) (mod c^3), where c is the n-th composite.at n=23A244214
• Numbers k such that (26*10^k - 107)/9 is prime.at n=22A275287
• Numbers that are the sum of five fourth powers in three or more ways.at n=35A344243
• Numbers that are the sum of five fourth powers in exactly three ways.at n=33A344244
• Irregular table read by rows: T(n,k) is the number of k-gons, k>=3, in a regular drawing of a complete bipartite graph where the vertex positions on each part equal the Farey series of order n.at n=21A359694
• Number of permutations (p(1),p(2),...,p(n)) of (1,2,...,n) such that p(i)-i is in {-2,3,4} for all i=1,...,n.at n=55A377715