OFFSET
1,1
COMMENTS
These numbers are all of the form 4m+1.
EXAMPLE
Triangle begins:
5;
17;
37;
5, 13;
101;
5, 29;
197;
257;
5, 5, 13;
401;
5, 97;
577;
...
MATHEMATICA
Flatten[Table[Table[First[#], {Last[#]}]&/@FactorInteger[4*n^2+1], {n, 60}]] (* Harvey P. Dale, Dec 19 2011 *)
PROG
(PARI) \\ here ifactor(n) gives n-th row of A027746.
ifactor(n) = { local(f, j, k, flist); flist=[]; f=Vec(factor(n)); for(j=1, length(f[1]), for(k = 1, f[2][j], flist = concat(flist, f[1][j]) ); ); return(flist) }
row(n)= { ifactor(4*n^2+1) }
CROSSREFS
KEYWORD
nonn,tabf,changed
AUTHOR
Cino Hilliard, Aug 26 2006
STATUS
approved