A330820 Numbers of the form (M_p^2-1)^2, where M_p is a Mersenne prime, A000668. Also the second element of the power-spectral basis of A330817.

64, 2304, 921600, 260112384, 4501400872550400, 295138898048817561600, 75557287266261531623424

Offset: 1

Author

Walter Kehowski, Jan 06 2020

Keywords

• nonn

Comments

The first element of the power-spectral basis of A330817 is A330819.

Examples

			If n=1, a(1)=(3^2-1)^2=64.
		

Crossrefs

Cf. A000043, A000668, A330817, A330818, A330819.

Programs

Maple

A330820:=[]:
for www to 1 do
for i from 1 to 31 do
#ithprime(31)=127
  p:=ithprime(i);
  q:=2^p-1;
if isprime(q) then x:=(q^2-1)^2; A330820:=[op(A330820),x] fi;
od;
od;
A330820;

Mathematica

Array[((2^MersennePrimeExponent[#] - 1)^2 - 1)^2 &, 10] (* Amiram Eldar, Jan 07 2020 *)

Formula

a(n) = (A000668(n)^2-1)^2.