Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #14 Jun 20 2016 19:39:16
%S 0,0,0,0,1,1,-1,-1,2,0,-2,0,3,0,-3,0,4,-2,-4,2,4,-3,-4,3,4,-5,-4,5,3,
%T -6,-3,6,2,-8,-2,8,1,-9,-1,9,0,-10,0,10,-2,-11,2,11,-4,-11,4,11,-6,
%U -12,6,12,-8,-12,8,12,-10,-11,10,11,-12,-10,12,10,-14,-9,14,9,-16,-8,16,8,-18,-7,18,7,-19,-5
%N a(n) = nearest integer to k*sin(sqrt(k)+j*Pi/2) where n = 4*k+j, 0<=j<4.
%H N. J. A. Sloane, <a href="/A274101/b274101.txt">Table of n, a(n) for n = 0..10000</a>
%p Digits:=50:
%p ft:=proc(n,t) local k,j;
%p j:=(n mod t); k:=(n-j)/t;
%p round(evalf(k*sin(sqrt(k)+j*Pi/2)));
%p end;
%p [seq(ft(n,4),n=0..120)];
%Y Sequences of the same type: A272695, A274086, A274087, A274088, A274090, A274091, A274092, A274095, A274096, A274097, A274101, A274102.
%K sign
%O 0,9
%A _N. J. A. Sloane_, Jun 11 2016
%E Definition corrected by _N. J. A. Sloane_, Jun 20 2016