A005657 a(n) = floor( tan(n)^2 ).

0, 2, 4, 0, 1, 11, 0, 0, 46, 0, 0, 51053, 0, 0, 52, 0, 0, 12, 1, 0, 5, 2, 0, 2, 4, 0, 1, 10, 0, 0, 41, 0, 0, 5672, 0, 0, 60, 0, 0, 13, 1, 0, 5, 2, 0, 2, 4, 0, 1, 10, 0, 0, 36, 0, 0, 2041, 0, 0, 69, 0, 0, 14, 1, 0, 5, 2, 0, 2, 4, 0, 1, 9, 0, 0, 32, 0, 0, 1041, 0, 0, 81, 0, 0, 15, 1, 0, 5, 2, 0, 2, 3, 0, 1, 8, 0, 0, 29, 0, 0, 629

Offset

0,2

Links

Robert Israel, Table of n, a(n) for n = 0..10000

R. K. Guy & N. J. A. Sloane, Correspondence, 1985

Formula

a(n) = A005699(n)-1 for n >= 1.

Maple

seq(floor(tan(n)^2), n=0..1000); # Robert Israel, Jun 14 2015

Mathematica

Floor[Tan[Range[0, 70]]^2] (* Harvey P. Dale, Nov 06 2011 *)

Prog

(PARI) vector(100, n, n--; floor(tan(n)^2)) \\ Michel Marcus, Jun 15 2015
(Magma) [Floor(Tan(n)^2): n in [0..100]]; // Vincenzo Librandi, Jun 15 2015

Crossrefs

Cf. A000503, A005699.

Sequence in context: A138133 A302937 A363367 * A009332 A333184 A045872

Adjacent sequences: A005654 A005655 A005656 * A005658 A005659 A005660

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved