A140423 a(n) = Sum_{k=1..n} k^(2^(n+1-k)).

1, 5, 26, 354, 72379, 4338080215, 18448597098193762724, 340282370354622283774333836315916425060, 115792089237316207213755562747271079374483128445080168204415615259394085515413

Offset

1,2

Comments

a(10) has 155 digits and is too large to show here. - Emeric Deutsch, Jul 20 2008

Links

Table of n, a(n) for n=1..9.

Maple

a:=proc(n) options operator, arrow: sum(k^(2^(n+1-k)), k=1..n) end proc: seq(a(n), n=1..8); # Emeric Deutsch, Jul 20 2008

Mathematica

Table[Sum[k^(2^(n+1-k)), {k, n}], {n, 10}] (* Harvey P. Dale, Mar 08 2012 *)

Crossrefs

Sequence in context: A295114 A060516 A077537 * A324419 A090644 A196951

Adjacent sequences: A140420 A140421 A140422 * A140424 A140425 A140426

Keyword

nonn

Author

Leroy Quet, Jun 18 2008

Extensions

More terms from Emeric Deutsch, Jul 20 2008

Status

approved