A210523 Record values of Dedekind psi function.

1, 3, 4, 6, 12, 18, 24, 36, 48, 72, 96, 108, 144, 168, 192, 216, 240, 288, 360, 384, 432, 576, 648, 672, 720, 864, 1008, 1152, 1296, 1344, 1440, 1728, 1800, 2016, 2304, 2592, 2880, 3024, 3456, 4032, 4320, 4608, 5184

Offset

1,2

Comments

Record values of A001615.

Links

Amiram Eldar, Table of n, a(n) for n = 1..808 (terms 1..373 from Enrique Pérez Herrero)

Formula

a(n) = A001615(A330006(n)). - Amiram Eldar, Nov 26 2019

Maple

N:= 100: # to get a(1) to a(N)
A001615 := proc(n) n*mul((1+1/i[1]), i=ifactors(n)[2]) end:
count:= 0:
val:= -infinity:
for i from 1 while count < N do
  v:= A001615(i);
  if v > val then
     val:= v;
       count:= count+1;
       A[count]:=v;
  fi
od:
seq(A[i], i=1..N); # Robert Israel, Nov 19 2014

Mathematica

JordanTotient[n_, k_:1] := DivisorSum[n, #^k*MoebiusMu[n/#]&] /; (n>0) && IntegerQ[n]; DedekindPsi[n_] := JordanTotient[n, 2]/EulerPhi[n]; a=1; lst={a}; Do[b=DedekindPsi[n]; If[b>a, a=b; AppendTo[lst, b]], {n, 2000}]; lst
psi[1] = 1; psi[n_] := n * Times @@ (1 + 1/FactorInteger[n][[;; , 1]]); seq = {}; pmax = 0; Do[pmax = psi[n]; If[p > pmax, pmax = p; AppendTo[seq, p]], {n, 1, 10^5}]; seq (* Amiram Eldar, Nov 26 2019 *)

Crossrefs

Cf. A002183, A006093, A330006 (the corresponding positions of records).

Sequence in context: A293593 A024373 A111159 * A109069 A329953 A329671

Adjacent sequences: A210520 A210521 A210522 * A210524 A210525 A210526

Keyword

nonn

Author

Enrique Pérez Herrero, Jan 27 2013

Status

approved