A122829 - OEIS

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A122829

Position of first occurrence of n in A121382.

1, 6, 24, 160, 30, 84, 60, 120, 180, 960, 360, 504, 1008, 210, 1470, 2550, 1050, 420, 630, 924, 840, 1260, 1320, 2184, 2520, 2640, 3120, 5712, 6120, 5040, 8400, 9360, 10080, 13440, 13200, 18900, 15120, 23760, 25200, 26400, 2310, 30240, 40320

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OFFSET

1,2

COMMENTS

Records are: 1, 6, 24, 30, 60, 120, 180, 210, 420, 840, 1260, 1320, 2184, 2310, 4620, 7140, 7980, 9240, ..., 30030, ....

LINKS

Table of n, a(n) for n=1..43.

MATHEMATICA

f[n_] := Block[{d = Divisors@n, m = DivisorSigma[0, n], s = {}}, If[m == 2, 1, Do[ AppendTo[s, {d[[p]], d[[q]], d[[r]]}], {r, m}, {q, r}, {p, q}]; Length@ Select[s, Times @@ # == n && GCD[ #[[1]], #[[2]]] == GCD[ #[[2]], #[[3]]] == 1 &]]]; t = Table[0, {125}]; Do[ a = f@n; If[ t[[a]] == 0, t[[a]] = n; Print[{a, n}]], {n, 43500}]

CROSSREFS

Cf. A121382.

Sequence in context: A330498 A165491 A165638 * A232688 A221980 A359693

Adjacent sequences: A122826 A122827 A122828 * A122830 A122831 A122832

KEYWORD

nonn

AUTHOR

Jonathan Vos Post and Robert G. Wilson v, Sep 12 2006

STATUS

approved