1,2

We write G12(r)=5*r^2-4*r and CG12(p)=6*p^2-6*p+1. A number has both properties iff there exist r and p such that 2*(5*r-2)^2=15*(2*p-1)^2+3. The diophantine equation (2*X)^2=30*Y^2+6 gives 2 new sequences. We obtain also 2 new sequences with the indices given by r and p respectively.

a(n+2)=482*a(n+1)-a(n)+312 ; a(n+1)=241*a(n)+156+44*(30*a(n)^2+39*a(n)+12)^0.5 ; G.f.: f(z)=a(1)*z+a(2)*z^2+...=(z+310*z^2+z^3)/((1-z)*(1-482*z+z^2))

Sequence in context: A133537 A075667 A136543 this_sequence A086393 A108251 A108252

Adjacent sequences: A133271 A133272 A133273 this_sequence A133275 A133276 A133277

nonn

Richard Choulet (richardchoulet(AT)yahoo.fr), Oct 16 2007