cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A028488 Numbers k such that the summatory Liouville function L(k) (A002819) is zero.

Original entry on oeis.org

2, 4, 6, 10, 16, 26, 40, 96, 586, 906150256, 906150294, 906150308, 906150310, 906150314, 906151516, 906151576, 906152172, 906154582, 906154586, 906154590, 906154594, 906154604, 906154606, 906154608, 906154758, 906154760, 906154762
Offset: 1

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Comments

a(253) > 2*10^14 according to the calculations of Borwein, Ferguson, & Mossinghoff. Most likely a(253) = 351100332278250. - Charles R Greathouse IV, Jun 14 2011
L(23156358837978983978) = 0 and L(k) < 0 for k from 2.3156354*10^19 to 23156358837978983977. - Hiroaki Yamanouchi, Oct 03 2015
All terms are even since k and A002819(k) have the same parity. - Jianing Song, Aug 06 2021
According to Pólya, numbers (p-3)/4 are members of this sequence, with p a Heegner number > 7 (that is, p is one of 11, 19, 43, 67, and 163). - Friedjof Tellkamp, Feb 15 2025

Crossrefs

Cf. A008836 (Liouville's function), A002819, A051470.
Cf. A003173 (Heegner numbers).

Programs

  • Maple
    B:= [seq((-1)^numtheory:-bigomega(i),i=1..10^5)]:
    L:= ListTools:-PartialSums(B):
    select(t -> L[t]=0, [$1..10^5]); # Robert Israel, Aug 27 2015
  • Mathematica
    Position[Table[Sum[LiouvilleLambda@ k, {k, 1, n}], {n, 1000}], n_ /; n == 0] // Flatten (* Michael De Vlieger, Aug 27 2015 *)
    Position[Accumulate[LiouvilleLambda[Range[1000]]],0]//Flatten (* Harvey P. Dale, Aug 10 2022 *)

Extensions

More terms from Hans Havermann, Jun 24 2002