A073588 a(n) = a(n-1)*2^n-1 with a(1)=1.

1, 3, 23, 367, 11743, 751551, 96198527, 24626822911, 12608933330431, 12911547730361343, 26442849751780030463, 108309912583291004776447, 887274803882319911128653823, 14537110386807929423931864236031

Offset

1,2

Links

Table of n, a(n) for n=1..14.

Formula

a(n) = ceiling(C*2^(n*(n+1)/2)) where C is a constant, C = 0.3583674393448461337061572297745... In fact, C = Sum_{k>=0} 1/2^(k*(k+1)/2) - 1/2^(k*(k+3)/2) = Sum_{k>=0} 1/2^A000217(k) - Sum_{k>=0} 1/2^A000096(k). - Benoit Cloitre, Sep 01 2002

a(n) = ceiling(C*2^(n*(n+1)/2)) where C is a constant, C = 0.3583674393448461337061572297745... - Benoit Cloitre, Sep 01 2002

Mathematica

a = 1; Table[a = a*2^n - 1, {n, 14}] (* Jayanta Basu, Jul 02 2013 *)

Crossrefs

Sequence in context: A092664 A363577 A260509 * A068338 A255881 A243195

Adjacent sequences: A073585 A073586 A073587 * A073589 A073590 A073591

Keyword

easy,nonn

Author

Felice Russo, Aug 28 2002

Extensions

Definition corrected by Georg Fischer, Jun 19 2021

Status

approved