OFFSET
1,1
COMMENTS
a(n) appears to be asymptotic to sqrt(8*n).
LINKS
Mats Granvik, Table of n, a(n) for n = 1..10000
Mats Granvik, More efficient Mathematica program for the sequence
Mats Granvik, What is the asymptotic of the irregular blue curve? Is it (8x)^(1/2) or is it something else?, MathOverflow, May 24 2020.
FORMULA
a(n) = 1 + Sum_{k=1..n} sign((sign(n+Sum_{j=2..k}-|A334312(n,j)|)+1)).
MATHEMATICA
nn = 80; varphi[n_] := DivisorSum[n, MoebiusMu[#] # &]; A = Table[Table[Sum[If[n >= k, varphi[GCD[i, k]], 0], {i, k, n}], {k, 1, nn}], {n, 1, nn}]; vv = Table[1 + Sum[Sign[(1 + Sign[Sum[If[j == 1, A[[n, j]], -Abs[A[[n, j]]]], {j, 1, k}]])], {k, 1, n}], {n, 1, nn}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Mats Granvik, May 24 2020
STATUS
approved