A133778 Odd primitive abundant numbers of the form (2*P)^2+2*P+p^2 with P and p primes and p^2<4*P.

15015, 41055, 46035, 5581695, 507263295, 756387555, 982365075, 1817713359, 1909933155, 2689720275, 2853976275, 4838941575, 5948000415, 6782922531, 7100171715, 13666199547, 13871855151, 14694980355, 16033285395, 16901775891, 22183878915, 22416851655, 24141235275

Offset

1,1

Links

Table of n, a(n) for n=1..23.

Example

15015   = 2*61*2*61     + 2*61   + 3*3;
41055   = 2*101*2*101   + 2*101  + 7*7;
46035   = 2*107*2*107   + 2*107  + 5*5;
5581695 = 2*1181*2*1181 + 2*1181 + 17*17.

Prog

(PARI) ispoa(n) = (n%2) && (sumdiv(n, d, sigma(d, -1)>2)==1); \\ A006038
lista(nn) = {forprime(P=2, nn, forprime(p=2, sqrtint(4*P), x = (2*P)^2+2*P+p^2; if (ispoa(x), print1(x, ", ")); ); ); } \\ Michel Marcus, Sep 15 2019

Crossrefs

Subsequence of A006038.

Sequence in context: A249263 A335052 A294026 * A200090 A147578 A285993

Adjacent sequences: A133775 A133776 A133777 * A133779 A133780 A133781

Keyword

nonn

Author

Pierre CAMI, Jan 02 2008

Extensions

More terms from Michel Marcus, Sep 15 2019

Status

approved