A274092 a(n) = nearest integer to k^2*sin(sqrt(k)+j*Pi/2) where n = 3*k+j, 0<=j<3.

0, 0, 0, 1, 1, -1, 4, 1, -4, 9, -1, -9, 15, -7, -15, 20, -15, -20, 23, -28, -23, 23, -43, -23, 20, -61, -20, 11, -80, -11, -2, -100, 2, -21, -119, 21, -46, -137, 46, -76, -151, 76, -111, -162, 111, -150, -167, 150, -194, -167, 194, -240, -161, 240, -289, -147, 289, -339, -125, 339, -389, -95, 389

Offset: 0

Author

N. J. A. Sloane, Jun 10 2016

Keywords

• sign

Links

• N. J. A. Sloane and Chai Wah Wu, Table of n, a(n) for n = 0..10000 n = 0..1000 from N. J. A. Sloane

Crossrefs

Sequences of the same type: A272695, A274086, A274087, A274088, A274090, A274091, A274092, A274095, A274096, A274097, A274101, A274102.

Programs

Maple

Digits:=50:
ft:=proc(n,t) local k,j;
j:=(n mod t); k:=(n-j)/t;
round(evalf(k^2*sin(sqrt(k)+j*Pi/2)));
end;
[seq(ft(n,3),n=0..120)];

Python

from sympy import sin, sqrt, pi
def A274092(n):
    k, j = divmod(n,3)
    return int((k**2*sin(sqrt(k)+j*pi/2)).round()) # Chai Wah Wu, Jun 10 2016