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A279254 Positive integers that have a record number of divisors in Gaussian integers. 6
1, 2, 4, 6, 8, 10, 20, 30, 40, 60, 100, 120, 180, 200, 240, 260, 300, 390, 520, 600, 780, 1200, 1300, 1560, 2340, 2600, 3120, 3900, 6630, 7800, 11700, 13260, 15600, 22100, 23400, 26520, 39780, 44200, 53040, 66300, 132600, 198900, 265200, 397800, 530400, 663000, 795600, 928200 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Indices of records in A062327.

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..394

MATHEMATICA

With[{s = Array[DivisorSigma[0, #, GaussianIntegers -> True] &, 10^6]}, Map[FirstPosition[s, #][[1]] &, Union@ FoldList[Max, s]]] (* Michael De Vlieger, Apr 05 2018 *)

PROG

(PARI)

b(n)= \\ A062327

{

    my(r=1, f=factor(n));

    for(j=1, #f[, 1], my(p=f[j, 1], e=f[j, 2]);

        if(p==2, r*=(2*e+1));

        if(p%4==1, r*=(e+1)^2);

        if(p%4==3, r*=(e+1));

    );

    return(r);

}

{ my(r=0, t); for(n=1, 10^6, t=b(n); if(t>r, r=t; print1(n, ", "))); }

\\ Joerg Arndt, Dec 09 2016

CROSSREFS

Subsequence of A097752.

Cf. A062327, A002182 (factorization over the integers).

Sequence in context: A254343 A157006 A221991 * A212495 A083490 A229363

Adjacent sequences:  A279251 A279252 A279253 * A279255 A279256 A279257

KEYWORD

nonn

AUTHOR

J. Lowell, Dec 08 2016

EXTENSIONS

Terms a(11) and beyond from Joerg Arndt, Dec 09 2016

STATUS

approved

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Last modified June 17 22:14 EDT 2021. Contains 345086 sequences. (Running on oeis4.)