A293751 Values of positive integer i such that floor(tan(-i)) = 1.

18, 21, 40, 43, 62, 65, 84, 87, 90, 106, 109, 112, 128, 131, 134, 150, 153, 156, 172, 175, 178, 197, 200, 219, 222, 241, 244, 263, 266, 285, 288, 307, 310, 329, 332, 351, 354, 373, 376, 395, 398, 417, 420, 439, 442, 445, 461, 464, 467, 483, 486, 489, 505, 508, 511, 527, 530, 533, 552, 555, 574, 577, 596

Offset: 1

Author

V.J. Pohjola, Oct 15 2017

Keywords

• nonn

Links

• Robert G. Wilson v, Table of n, a(n) for n = 1..1040

Crossrefs

Cf. A000530, A293698, A293699, A293702, A293705, A293700, A293701, A293704. a(n) are also the roots of A195910(i)=1, starting from i=1.

Programs

Mathematica

rootsn = Flatten[Position[Table[Floor[Tan[-i]], {i, 1, 10^3}], 1]];
(*a(n) = rootsn[[n]]*)
Select[Range@600, Floor@Tan@-# == 1 &] (* Robert G. Wilson v, Nov 19 2017 *)

PARI

isok(n) = floor(tan(-n)) == 1; \\ Michel Marcus, Nov 03 2017

Formula

floor(tan(-n)) = -ceiling(tan(n)).