A136477 Numbers x such that for some y < sqrt(2x), x^2 + x + y^2 is an odd primitive abundant number, A136476(n).

97, 112, 122, 135, 144, 179, 202, 207, 214, 217, 227, 354, 359, 477, 507, 569, 612, 632, 639, 732, 832, 2124, 2359, 2362, 2440, 2466, 2517, 2970, 3097, 3247, 3342, 3367, 3374, 3419, 3425, 3518, 3545, 3562, 3644, 3672, 3699, 3789, 3879, 3969, 3985, 4050

Offset

1,1

Comments

The corresponding y-values are listed in A136478. (Unlike the x-values listed here, y is not increasing with A136476(n).)

Links

Table of n, a(n) for n=1..46.

Example

97^2 + 97 + 7^2 = 9555 = A136476(1) is an odd primitive abundant number, so a(1) = 97.

Prog

(PARI) is(x, n=x^2+x+1, f)={forstep(y=1, sqrtint(2*x), 2, sigma(n+=y*4-4, -1)>2 || next; for(i=1, #f=factor(n)[, 1], sigma(n\f[i], -1)>2 && next(2)); return(1))} \\ M. F. Hasler, Feb 22 2017

Crossrefs

Cf. A006038, A136476, A136478, A136479.

Sequence in context: A039490 A033202 A160032 * A078494 A139980 A140830

Adjacent sequences: A136474 A136475 A136476 * A136478 A136479 A136480

Keyword

nonn

Author

Pierre CAMI, Dec 31 2007

Extensions

Edited by M. F. Hasler, Feb 22 2017

Status

approved