19180

Appears in sequences

• Number of regions in regular n-gon with all diagonals drawn.at n=27A007678
• Expansion of e.g.f. sin(arctan(x) + log(x+1)).at n=8A012961
• sin(arctanh(x) + log(x+1)) = 2*x - 1/2!*x^2 - 4/3!*x^3 + 18/4!*x^4 - 110/5!*x^5 + ...at n=8A013156
• A list of equal temperaments (equal divisions of the octave) whose nearest scale steps are closer and closer approximations to the pair of ratios 6/5 and 5/3 which generate two complementary musical harmonies, the Minor 3rd (6/5) and the Major 6th (5/3).at n=23A061919
• a(n) = floor(Pi^n mod n^Pi).at n=40A066434
• Radius of inscribed circle within primitive Pythagorean triangles having legs that add up to a square, sorted on hypotenuse.at n=44A089551
• a(n) = 3^(n+1) - 2^(n+1) + n + 1.at n=8A094618
• Least m such that both p|m and p+2|m+2 for twin prime pairs (p,p+2) (p=A001359).at n=10A097972
• a(n) = prime(n)*(prime(n+1) + 1).at n=32A123134
• Number of reduced words of length n in Coxeter group on 8 generators S_i with relations (S_i)^2 = (S_i S_j)^5 = I.at n=5A163347
• Triangle read by rows: T(n,k) is the number of stretching pairs in all permutations in S_{n,k} (=set of permutations in S_n with k cycles) (n >= 3; 1 <= k <= n-2).at n=16A216118
• Number T(n,k) of tilings of a 5 X n rectangle with pentominoes of any shape and exactly k pentominoes of shape T; triangle T(n,k), n>=0, 0<=k<=max(0,floor(2*(n-1)/3)), read by rows.at n=43A247707
• Numbers n such that sigma(n) is a Fibonacci number.at n=11A272412
• Number of regions in an equal-armed cross with arms of length n (see Comments for definition).at n=6A331456
• Numbers whose divisors can be partitioned into two disjoint sets whose sums are consecutive Fibonacci numbers.at n=5A333677
• Primitive practical numbers (A267124) with a record gap to the next primitive practical number.at n=11A334883