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URL: https://oeis.org/A034168

⇱ A034168 - OEIS

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A034168
Disjoint discriminants (one form per genus) of type 2 (doubled).
3
2, 6, 10, 22, 30, 42, 58, 70, 78, 102, 130, 190, 210, 330, 462
OFFSET
1,1
REFERENCES
J. M. Borwein and P. B. Borwein, Pi and the AGM, page 293.
L. E. Dickson, Introduction to the theory of numbers, Dover, NY, 1929.
LINKS
Jonathan M. Borwein, Adventures with the OEIS: Five sequences Tony may like, Guttmann 70th [Birthday] Meeting, 2015, revised May 2016.
Jonathan M. Borwein, Adventures with the OEIS: Five sequences Tony may like, Guttmann 70th [Birthday] Meeting, 2015, revised May 2016. [Cached copy, with permission]
Jonathan Borwein and Kwok-Kwong Stephen Choi, On the representations of xy+yz+zx, Experimental Mathematics, 9 (2000), 153-158.
FORMULA
Intersection of A005843 and A139826. - Andrew Howroyd, Jun 09 2018
MATHEMATICA
noSol = {};
Do[lim = Ceiling[(n-2)/3]; found = False; Do[If[n > a*b && Mod[n - a*b, a+b] == 0 && Quotient[n - a*b, a+b] > b, found = True; Break[]], {a, 1, lim-1}, {b, a+1, lim}]; If[!found, AppendTo[noSol, n]], {n, 1000}];
Select[noSol, EvenQ[#] && SquareFreeQ[#]&] (* Jean-François Alcover, Jul 21 2022, after T. D. Noe in A000926 *)
PROG
(PARI) ok(n)={n%4==2 && issquarefree(n) && !select(t->t<>2, quadclassunit(-4*n).cyc)} \\ Andrew Howroyd, Jun 09 2018
CROSSREFS
Cf. A000926, A005843, A034169, A055745, A139826. Subsequence of A025052.
Sequence in context: A140775 A077064 A080715 * A055745 A371283 A387724
KEYWORD
nonn,fini,full,nice
AUTHOR
Jonathan Borwein (jborwein(AT)cecm.sfu.ca), choi(AT)cecm.sfu.ca (Stephen Choi)
STATUS
approved