66849

Appears in sequences

• sec(arcsin(arctanh(x)))=1+1/2!*x^2+17/4!*x^4+769/6!*x^6+66849/8!*x^8...at n=4A012144
• Expansion of e.g.f. exp(arctanh(arctanh(x))).at n=8A012263
• Number of (n+1) X 3 binary arrays with rows and columns in nondecreasing order and with no 2 X 2 subblock sum differing from a horizontal or vertical neighbor subblock sum by more than one.at n=37A184064
• Number of subsets of {1..n} containing no differences or quotients of pairs of distinct elements.at n=26A326490