OFFSET
1,1
COMMENTS
The third number that is a sum of n positive n-th powers. - Alois P. Heinz, Aug 02 2020
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (4,-5,2).
FORMULA
a(1) = 3; a(n) = a(n-1) + 2^n + 1 for n > 1.
a(n) = 2^(n+1) + n - 2. - Franklin T. Adams-Watters, Jul 06 2009
G.f.: x*(3-4*x)/((1-x)^2*(1-2*x)). - Colin Barker, Jan 11 2012
EXAMPLE
a(2) = a(1) + 2^2 + 1 = 3 + 4 + 1 = 8; a(3) = a(2) + 2^3 + 1 = 8 + 8 + 1 = 17.
MATHEMATICA
lst={}; s=0; Do[s+=2^n+1; AppendTo[lst, s], {n, 5!}]; lst
Accumulate[2^Range[30]+1] (* Harvey P. Dale, Feb 19 2023 *)
PROG
(ARIBAS) a:=0; for n:=1 to 30 do a:=a+2**n+1; write(a, ", "); end;
(Haskell)
a145071 n = 2 ^ (n + 1) + n - 2
a145071_list = scanl1 (+) $ tail a000051_list
-- Reinhard Zumkeller, Nov 16 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vladimir Joseph Stephan Orlovsky, Sep 30 2008
EXTENSIONS
Edited by Klaus Brockhaus, Oct 14 2008
STATUS
approved