A348557 - OEIS

%I #15 Dec 15 2021 23:07:38

%S 30,42,70,90,102,120,154,165,170,180,182,198,210,220,224,230,238,255,

%T 264,270,273,285,286,306,308,322,330,340,350,360,374,380,385,399,406,

%U 418,420,434,435,442,465,480,486,490,494,495,506,510,518,525,544,546,550,552,558

%N List of indices k such that A327267(k) is less than A328666(k).

%C It is known that A327267(n) <= A328666(n) for all n. See link. For n up to 6000, the inequality is strict only for 1193 values of n.

%C Indeed, the purpose of A328666 is to give a good upper bound sequence for the sequence A327267, while being much easier to compute.

%H Christopher J. Smyth, <a href="/A348557/b348557.txt">Table of n, a(n) for n = 1..1193</a>

%H Chris Pinner and Chris Smyth, <a href="/A348557/a348557.pdf">Lattices of minimal index in Z^n having an orthogonal basis containing a given vector</a>, preprint, 2021.

%e a(1) = 30 since 30 is the first value of k for which A327267(k) < A328666(k).

%Y Cf. A327267 and A328666.

%K nonn

%O 1,1

%A _Christopher J. Smyth_, Oct 22 2021