22734

Appears in sequences

• a(n) = a(n-1) + a(n-2) + 1, with a(0) = 1 and a(1) = 12.at n=17A022326
• Numbers n such that n divides the (right) concatenation of all numbers <= n written in base 10 (most significant digit on right).at n=20A029503
• Let (u1,u2) be successive untouchable numbers such that phi(u1) = phi(u2); sequence gives values of u2.at n=41A048190
• Number of cubic lattice walks that start and end at origin after 2n steps, not touching origin at intermediate stages.at n=4A049037
• Integers y such that for some integer x we have uphi(x) = uphi(y) = x-y, where uphi(n) = A047994(n) is the unitary totient function: If n = Product p_i^e_i, uphi(n) = Product (p_i^e_i - 1).at n=12A067741
• Triangle read by rows: T[n,k] = number of n X n binary matrices with k=0...n^2 ones, distinct up to cyclic shifts of rows and columns; reflection through any vertical or horizontal axis; and reflection through the main diagonal. Also, quasi-n-ominoes on a torus divided into a k X k grid.at n=45A093466
• Triangle read by rows: T[n,k] = number of n X n binary matrices with k=0...n^2 ones, distinct up to cyclic shifts of rows and columns; reflection through any vertical or horizontal axis; and reflection through the main diagonal. Also, quasi-n-ominoes on a torus divided into a k X k grid.at n=48A093466
• Expansion of x/((1 - x - x^4)*(1 - x)^2).at n=26A145131
• 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, -1, 0), (-1, 1, 0), (1, -1, 1), (1, 0, -1), (1, 0, 1)}.at n=9A148885
• Numbers m such that m, m' and m'' are in arithmetic progression, where m' and m'' are the first and second arithmetic derivatives of m.at n=21A212409
• The Wiener index of the dendrimer D_3[n], defined pictorially in the A. R. Ashrafi et al. reference.at n=1A224433
• Number of (n+2)X(n+2) 0..2 matrices with each 3X3 subblock idempotent.at n=10A224598
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 214", based on the 5-celled von Neumann neighborhood.at n=39A270907
• Number of n X 1 0..2 arrays with no element unequal to a strict majority of its horizontal and vertical neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.at n=13A279865
• Number of n X 2 0..2 arrays with no element unequal to a strict majority of its horizontal and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.at n=6A280474
• T(n,k)=Number of nXk 0..2 arrays with no element unequal to a strict majority of its horizontal and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.at n=34A280480
• Numbers k such that 8k+1, 12k+1 and 24k+1 are primes and the last two are also of the form x^2 + 27y^2, so the tetrahedral number T(24k+1) is a Fermat pseudoprime to base 2.at n=17A321867
• Composite k such that the primorial inflation of k is a sum of distinct primorial numbers.at n=22A351959
• Number A(n,k) of k-dimensional cubic lattice walks with 2n steps from origin to origin and avoiding early returns to the origin; square array A(n,k), n>=0, k>=0, read by antidiagonals.at n=32A361397
• a(n) is the largest number t such that there exist numbers i,j,k such that, for all m <= t, there exist integers x,y,z with x*i + y*j + z*k = m and |x|+|y|+|z| <= n.at n=38A383579