41721

Appears in sequences

• a(n) = floor( tan(m*Pi/2) ), where m = 1 - 2^(-n).at n=15A024810
• Number of binary strings of length n with no substrings equal to 0000 0101 or 0110.at n=16A164432
• Composite numbers and 1 which yield a prime whenever a 7 is inserted anywhere in them, including at the beginning or end.at n=44A216168
• E.g.f. A(x) satisfies A(x) = 1 + (1 - exp(-x)) * A(2 * (1 - exp(-x))).at n=5A355123