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A326313
Where the number of divisors d(k) reaches a new record for numbers k whose prime factors are of the form 4*j+3.
3
3, 9, 21, 63, 189, 441, 567, 693, 2079, 4851, 6237, 13167, 39501, 92169, 118503, 276507, 829521, 908523, 2119887, 2725569, 6359661, 19078983, 28164213, 57236949, 84492639, 171710847, 197149491, 591448473, 1211061159, 1774345419, 3633183477, 5323036257, 6505933203
OFFSET
1,1
COMMENTS
For references and links see A326312.
LINKS
MATHEMATICA
aQ[n_] := AllTrue[FactorInteger[n][[;; , 1]], Mod[#, 4] == 3 &]; s[n_] := DivisorSum[n, 1 &, aQ[#] &]; sm = 0; seq = {}; Do[s1 = s[n]; If[s1 > sm, sm = s1; AppendTo[seq, n]], {n, 2, 10^5}]; seq (* Amiram Eldar, Sep 12 2019 *)
PROG
(PARI) pkn(x, d, m)={my(fn=factor(x), nf=#fn[, 1]); for(k=1, nf, if(fn[k, 1]%d!=m, return(0))); numdiv(x)};
divrecord=0;
for(k=2, 50000000, my(j=pkn(k, 4, 3)); if(j>divrecord, divrecord=j; print1(k, ", ")))
CROSSREFS
KEYWORD
nonn
AUTHOR
Hugo Pfoertner, Sep 11 2019
EXTENSIONS
More terms from Amiram Eldar, Sep 12 2019
STATUS
approved