23807

Appears in sequences

• Expansion of e.g.f. log(arctan(x) + exp(x)).at n=7A012972
• a(n) = floor( sqrt(2) * (3/2)^n ).at n=24A033320
• Numbers k such that 61*2^k-1 is prime.at n=30A050556
• Number of 3-element proper antichains (i.e., antichains such that every two members have nonempty intersection) on an unlabeled n-element set.at n=16A056782
• Positive numbers of the form x^5-10x^3*y^2+5x*y^4 (where x,y are integers and y>x).at n=18A135792
• Numbers of the form x^5-10x^3*y^2+5x*y^4 (where x,y are integers).at n=24A135793
• a(n) = ((7 + sqrt(2))^n + (7 - sqrt(2))^n)/2.at n=5A147958
• Number of n X 2 0..2 arrays with horizontal differences mod 3 never 1, vertical differences mod 3 never -1, and rows and columns lexicographically nondecreasing.at n=26A229439
• Smallest k such that A257743(k)=n.at n=26A257744
• Positive numbers k such that k and k + 1 are both positive negaFibonacci-Niven numbers (A331085) and -k and -(k + 1) are both negative negaFibonacci-Niven numbers (A331088).at n=37A331092