A279106 a(n) = number of legs in each part of the symmetric representation of sigma(A279105(n)).
1, 3, 7, 11, 15, 23, 31, 35, 39, 47, 55, 59, 63, 71, 79, 83, 95, 107, 111, 119, 127, 131, 143, 159, 167, 175, 179, 191, 199, 207, 215, 223, 239, 251, 255, 263, 279, 287, 299, 311, 319, 323, 335, 351, 359, 383, 391, 395, 399, 407, 415, 419, 431, 439, 447, 455, 467, 479
Offset: 1
Keywords
Examples
a(3) = 7 = 2 * A279105(3) - 1; 21 is not in the sequence since 11=(21+1)/2 is not in A174793.
Programs
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Mathematica
a174973Q[n_] := Module[{d=Divisors[n]}, Select[Rest[d] - 2*Most[d], #>0&]=={}] a279106[n_]:=2*Select[Range[n], a174973Q] - 1 a279106[250] (* sequence data *)
Formula
a(n) = 2 * A279105(n) - 1.