The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A335130 a(n) = 1 + Sum_{k=1..n} sign((sign(n+Sum_{j=2..k}-|A334312(n,j)|)+1)). 1
 2, 3, 4, 5, 6, 5, 7, 7, 10, 7, 11, 10, 11, 10, 11, 11, 14, 13, 14, 13, 13, 11, 15, 12, 17, 13, 17, 13, 19, 13, 14, 15, 15, 15, 17, 17, 17, 19, 19, 17, 19, 17, 18, 17, 17, 18, 21, 19, 22, 21, 21, 19, 21, 21, 23, 23, 19, 19, 26, 19, 19, 23, 23, 23, 29, 21, 22, 21, 23, 21, 23, 22, 23, 23, 28, 23, 31, 23, 26, 25 (list; graph; refs; listen; history; text; internal format)
 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 Cf. A334312. Sequence in context: A099033 A187786 A002330 * A305900 A287943 A305211 Adjacent sequences:  A335127 A335128 A335129 * A335131 A335132 A335133 KEYWORD nonn AUTHOR Mats Granvik, May 24 2020 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified September 22 12:34 EDT 2020. Contains 337289 sequences. (Running on oeis4.)