A055042 Numbers of the form 2^(2i+1)*(8*j+5).

10, 26, 40, 42, 58, 74, 90, 104, 106, 122, 138, 154, 160, 168, 170, 186, 202, 218, 232, 234, 250, 266, 282, 296, 298, 314, 330, 346, 360, 362, 378, 394, 410, 416, 424, 426, 442, 458, 474, 488, 490, 506, 522, 538, 552, 554, 570, 586, 602, 616

Offset

1,1

Comments

These are also the numbers not of the form x^2+2y^2+3z^2.

References

B. W. Jones, The Arithmetic of Quadratic Forms, Carus Monograph 10, Math. Assoc. America, 1967; Problem 60, p. 204.

Links

David A. Corneth, Table of n, a(n) for n = 1..10000

L. J. Mordell, A new Waring's problem with squares of linear forms, Quart. J. Math., 1 (1930), 276-288 (see p. 283).

Example

42 = 21*2 = 2^(2*0 + 1)*(8*2 + 5) is in the sequence. - David A. Corneth, Apr 18 2021

Prog

(PARI) upto(n) = { my(res = List()); for(i = 0, logint(n\2, 2), forstep(j = 5, n>>(2*i+1), 8, listput(res, 4^i*2*j) ) ); Set(res) } \\ David A. Corneth, Apr 18 2021

Crossrefs

Sequence in context: A080059 A071348 A361259 * A044071 A186279 A054315

Adjacent sequences: A055039 A055040 A055041 * A055043 A055044 A055045

Keyword

nonn,easy

Author

N. J. A. Sloane, Jun 01 2000

Status

approved