login

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”).

A299639
a(0) = 0, and for n > 0, (a(n)) gives the indices n for which d(n) > d(k) for k < n, where d is the difference sequence of (cos k + sin k).
1
0, 4, 5, 52168, 52878, 53588, 54298, 55008, 55718, 56428, 57138, 57848, 58558, 59268, 59978, 60688, 61398, 62108, 62818, 63528, 64238, 64948, 65658, 66368, 67078, 67788, 68498, 69208, 69918, 70628, 71338, 72048, 72758, 73468, 74178, 74888, 75598, 76308
OFFSET
0,2
COMMENTS
Conjecture: d(n) -> 1.356...
EXAMPLE
Records for n - 0,1,2, read from the first 6 values of d(n) approximated by
0.381, -0.088, -1.34, -0.56, 0.73, 1.35; viz.,
d(0) = cos(1) + sin(1) - cos(0) - sin(0) = 0.38177...
d(4) = cos(5) + sin(5) - cos(4) - sin(4) = 0.73518...
d(5) = 1.356016878...
d(52168) = 1.356016794...
MATHEMATICA
z = 100000; d[n_] := N[Cos[n + 1] + Sin[n + 1] - Cos[n] - Sin[n], 10];
max = d[0]; k = 0; s = {0};
While[k < z, a = d[k]; If[a > max, max = a; AppendTo[s, k]]; k++]; s
CROSSREFS
Cf. A299640.
Sequence in context: A270975 A058916 A064612 * A244444 A231407 A005927
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Apr 08 2018
STATUS
approved