A136477 - OEIS

%I #8 Feb 23 2017 22:33:55

%S 97,112,122,135,144,179,202,207,214,217,227,354,359,477,507,569,612,

%T 632,639,732,832,2124,2359,2362,2440,2466,2517,2970,3097,3247,3342,

%U 3367,3374,3419,3425,3518,3545,3562,3644,3672,3699,3789,3879,3969,3985,4050

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

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

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

%o (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

%Y Cf. A006038, A136476, A136478, A136479.

%K nonn

%O 1,1

%A _Pierre CAMI_, Dec 31 2007

%E Edited by _M. F. Hasler_, Feb 22 2017