A330754 - OEIS

A330754

Number of values of k, 1 <= k <= n, with A330691(k) = A330691(n), where A330691(n) = gcd(n, A309639(n)).

1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 2, 3, 1, 1, 2, 1, 4, 3, 2, 1, 4, 1, 2, 1, 3, 1, 5, 1, 1, 3, 2, 4, 3, 1, 2, 3, 2, 1, 5, 1, 4, 4, 2, 1, 2, 1, 2, 3, 4, 1, 2, 5, 3, 3, 2, 1, 6, 1, 2, 5, 1, 5, 6, 1, 4, 6, 5, 1, 6, 1, 2, 3, 4, 7, 6, 1, 3, 1, 2, 1, 7, 5, 2, 3, 8, 1, 7, 7, 3, 3, 2, 5, 2, 1, 2, 9, 4, 1, 6, 1, 8, 8

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OFFSET

1,6

COMMENTS

Ordinal transform of A330691.

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..65537

MATHEMATICA

A309639[n_] := For[k = 1, True, k++, If[Divisible[Denominator[ HarmonicNumber[k]], n], Return[k]]];

A330691[n_] := GCD[n, A309639[n]];

Module[{b}, b[_] = 0;

a[n_] := With[{t = A330691[n]}, b[t] = b[t] + 1]];

Array[a, 105] (* Jean-François Alcover, Jan 11 2022 *)

PROG

(PARI)

A330691(n) = gcd(n, A309639(n));

ordinal_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), pt); for(i=1, length(invec), if(mapisdefined(om, invec[i]), pt = mapget(om, invec[i]), pt = 0); outvec[i] = (1+pt); mapput(om, invec[i], (1+pt))); outvec; };

v330754 = ordinal_transform(vector(up_to, n, A330691(n)));

A330754(n) = v330754[n];

CROSSREFS

Cf. A309639, A330691, A330753.

Sequence in context: A324369 A276781 A303759 * A330753 A082068 A300360

Adjacent sequences: A330751 A330752 A330753 * A330755 A330756 A330757

KEYWORD

nonn

AUTHOR

Antti Karttunen, Dec 30 2019

STATUS

approved