41000

Appears in sequences

• Number of rooted triangular cacti with 2n+1 nodes (n triangles).at n=11A003080
• Numbers whose base-4 representation contains exactly four 0's and four 2's.at n=22A045061
• Each permutation in the list A060117 converted to Site Swap notation, with digits reversed. "Zero throws" (fixed elements) indicated with 0's.at n=24A060496
• Łukasiewicz word for each rooted plane tree (interpretation e in Stanley's exercise 19) encoded by A014486 (or A063171), with the last leaf implicit, i.e., these words are given without the last trailing zero, except for the null tree which is encoded as 0.at n=37A071153
• Numbers k such that k and k^2 use only the digits 0, 1, 4, 6 and 8.at n=54A136861
• a(n) = numerator of fraction a/b, where gcd(a, b) = 1, whose decimal representation has the form (1)(2)(3)...(n-1)(n).(1)(2)(3)...(n-1)(n)... with period (1)(2)(3)...(n-1)(n).at n=2A172505
• Numbers n such that phi(n)/n = 16/41.at n=16A176598
• a(n) = (9*n+2)*(9*n+7).at n=22A177072
• Łukasiewicz words (without the last zero) for rooted plane trees where non-leaf branching can occur only at the leftmost branch of any level, but nowhere else.at n=17A209644
• Number T(n,k) of equivalence classes of ways of placing k 2 X 2 tiles in an n X 9 rectangle under all symmetry operations of the rectangle; irregular triangle T(n,k), n>=2, 0<=k<=4*floor(n/2), read by rows.at n=36A238581
• Number of n X 2 0..3 arrays with no element equal to zero plus the sum of elements to its left or one plus the sum of elements above it or zero plus the sum of the elements diagonally to its northwest or zero plus the sum of the elements antidiagonally to its northeast, modulo 4.at n=22A241301
• Sequence A261220 shown in factorial base: a(n) = A007623(A261220(n)).at n=60A260743
• Decimal representation of the x-axis, from the origin to the right edge, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 777", based on the 5-celled von Neumann neighborhood.at n=17A283917
• Row sums of irregular triangle A070168.at n=54A285098
• Number of partitions of 3*n that have exactly n prime parts.at n=38A299731
• Least number k such that the determinant of the circulant matrix formed by its decimal digits is equal to k/n.at n=39A323485
• Number of triangular regions in a "frame" of size n X n (see Comments in A331776 for definition), divided by 4.at n=25A332595