login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A329004 a(n) is the largest index in [n] that maximizes tau. 1
1, 2, 3, 4, 4, 6, 6, 8, 8, 10, 10, 12, 12, 12, 12, 12, 12, 18, 18, 20, 20, 20, 20, 24, 24, 24, 24, 24, 24, 30, 30, 30, 30, 30, 30, 36, 36, 36, 36, 36, 36, 36, 36, 36, 36, 36, 36, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 72 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Peter Andrew, Table of n, a(n) for n = 1..20000

FORMULA

a(n) = n <=> n in { A067128 }. - Alois P. Heinz, Jun 11 2020

MAPLE

a:= proc(n) option remember; uses numtheory; `if`(n=1, 1,

(t-> `if`(tau(n)<tau(t), t, n))(a(n-1)))

end:

seq(a(n), n=1..100); # Alois P. Heinz, Jun 11 2020

MATHEMATICA

dmax = 0; nmax = 1; seq = {}; Do[If[(d = DivisorSigma[0, n]) >= dmax, dmax = d; nmax = n]; AppendTo[seq, nmax], {n, 1, 72}]; seq (* Amiram Eldar, Jun 11 2020 *)

PROG

(Haskell) a329004 = map fst $ scanl1 (\x y -> maximumBy (comparing snd) [x, y]) $ zip [1..] a000005

CROSSREFS

Cf. A000005, A067128.

Sequence in context: A111939 A253248 A341112 * A003962 A102443 A102441

Adjacent sequences: A329001 A329002 A329003 * A329005 A329006 A329007

KEYWORD

nonn

AUTHOR

Peter Andrew, Jun 10 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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified February 7 12:25 EST 2023. Contains 360116 sequences. (Running on oeis4.)