1,1

O. E. Pol, Determinacion geometrica de los numeros primos y perfectos.

a(n)=A000668(n)*A135623(n).

a(3)=403 because the 3rd. Mersenne prime is 31 and 31*13=403.

read transforms : A000043 := proc(n) op(n, [2, 3, 5, 7, 13, 17, 19, 31, 61, 89, 107, 127, 521, 607, 1279, 2203, 2281, 3217, 4253, 4423, 9689, 9941, 11213, 19937]) ; end: A000668 := proc(n) 2^A000043(n)-1 ; end: A135623 := proc(n) digrev(A000668(n)) ; end: A135625 := proc(n) A000668(n)*A135623(n) ; end: for n from 1 to 13 do printf("%d, ", A135625 (n) ) ; od: - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Feb 28 2008

Cf. A000668, A133019, A135623.

Sequence in context: A090390 A069665 A066558 this_sequence A115326 A069666 A133049

Adjacent sequences: A135622 A135623 A135624 this_sequence A135626 A135627 A135628

base,nonn

Omar E. Pol (info(AT)polprimos.com), Feb 20 2008

More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Feb 28 2008