A279187 - OEIS

A279187

Maximal entry in row c of A279185, where c = n-th composite number A002808(n).

1, 1, 1, 2, 1, 1, 2, 1, 1, 2, 1, 2, 4, 1, 4, 2, 6, 2, 1, 1, 4, 1, 2, 2, 6, 2, 1, 2, 4, 2, 10, 1, 6, 4, 1, 2, 6, 4, 2, 6, 3, 1, 4, 2, 1, 2, 4, 1, 10, 2, 2, 6, 4, 6, 4, 2, 1, 18, 4, 2, 1, 6, 3, 4, 2, 2, 10, 4, 11, 6, 1, 6, 4, 4, 1, 2, 2, 12, 6, 4, 6, 2, 6, 10, 3, 2

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OFFSET

1,4

COMMENTS

There are really two sequences that should be included if missing: the maximal entry in row c, and the LCM of the entries in row c.

a(n) and the LCM variant A256608(A002808(n)) are equal at least up to n<=1100. - R. J. Mathar, Dec 15 2016

LINKS

R. J. Mathar, Table of n, a(n) for n = 1..1000

Haifeng Xu, The largest cycles consist by the quadratic residues and Fermat primes, arXiv:1601.06509 [math.NT], 2016.

MAPLE

A279187 := proc(n)

A279186(A002808(n)) ;

end proc :

seq(A279187(n), n=1..180) ; # R. J. Mathar, Dec 15 2016

MATHEMATICA

T[n_, k_] := Module[{g, y, r}, If[k == 0, Return[1]]; y = n; g = GCD[k, y]; While[g > 1, y = y/g; g = GCD[k, y]]; If[y == 1, Return[1]]; r = MultiplicativeOrder[k, y]; r = r/2^IntegerExponent[r, 2]; If[r == 1, Return[1]]; MultiplicativeOrder[2, r]]; Composite[n_] := FixedPoint[n + PrimePi[#] + 1&, n + PrimePi[n] + 1];

a[n_] := a[n] = With[{c = Composite[n]}, Table[T[c, k], {k, 0, c-1}] // Max ];

Table[Print["a(", n, ") = ", a[n]]; a[n], {n, 1, 86}] (* Jean-François Alcover, Nov 27 2017, after Robert Israel *)

CROSSREFS

Cf. A002808, A256608 (lcm of entries in row n), A279185, A279186 (max entry in row n).

Sequence in context: A025433 A025434 A111178 * A254434 A076845 A161906

Adjacent sequences: A279184 A279185 A279186 * A279188 A279189 A279190

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Dec 14 2016

STATUS

approved