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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A080742 Largest element of n-th row of A080738. 4

%I

%S 2,6,12,30,60,120,210,420,840,1260,2520,2310,5040,9240,13860,27720,

%T 32760,55440,65520,120120,180180,360360,235620,720720,556920,942480,

%U 1113840,1531530

%N Largest element of n-th row of A080738.

%H J. Bamberg, G. Cairns and D. Kilminster, <a href="http://www.jstor.org/stable/3647934">The crystallographic restriction, permutations and Goldbach's conjecture</a>, Amer. Math. Monthly, 110 (March 2003), 202-209.

%t a080737[1] = a080737[2] = 0; a080737[p_?PrimeQ] := a080737[p] = p - 1; a080737[n_] := a080737[n] = If[Length[fi = FactorInteger[n]] == 1, EulerPhi[n], Total[a080737 /@ (fi[[All, 1]]^fi[[All, 2]])]]; orders = Table[{n, a080737[n]}, {n, 1, 2*10^6}]; row[0] = {1, 2}; row[n_] := Select[orders, 2*n - 1 <= #[[2]] <= 2*n &][[All, 1]]; Table[ row[n] // Last, {n, 0, 27}] (* _Jean-François Alcover_, Jul 24 2013 *)

%o (Haskell)

%o a080742 n k = a080742_list !! n

%o a080742_list = map last a080738_tabf -- _Reinhard Zumkeller_, Jun 13 2012

%Y Cf. A080737, A080738, A080740, A080741, A005417.

%K nonn,more

%O 0,1

%A _N. J. A. Sloane_, Mar 08 2003

%E Corrected and extended by _Vladeta Jovovic_, Mar 09 2003

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 1 11:59 EDT 2020. Contains 337443 sequences. (Running on oeis4.)