60273
domain: N
Appears in sequences
- a(0)=1, a(1)=1, a(n) = 9*a(n/2) for even n >= 2, and a(n) = 8*a((n-1)/2) + a((n+1)/2) for odd n >= 3.at n=38A116526
- Numbers k such that if you subtract k-reversed from k you get a natural number with the same digits as k.at n=18A121969
- Number of ways to arrange 2 nonattacking knights on the lower triangle of an n X n board.at n=25A194486
- Number of (n+1) X (7+1) 0..1 arrays with every 2 X 2 subblock diagonal minimum minus antidiagonal minimum nondecreasing horizontally and diagonal maximum minus antidiagonal maximum nondecreasing vertically.at n=8A253230
- Place two n-gons with radii 1 and 2 concentrically, forming an annular area between them. Connect all the vertices with line segments that lie entirely within that area. Then a(n) is the number of regions in that figure.at n=34A337700
- Numbers k such that A003415(k) >= A276086(k) and gcd(k, A003415(k)) = gcd(k, A276086(k)) > 1, where A003415 is the arithmetic derivative, and A276086 is the primorial base exp-function.at n=8A369960