OFFSET
0,4
COMMENTS
a(33899) = 123729 and the 33900th prime is 400559, hence 123729 + 400559 = 524288 = 2^19 and a(33900) = 1. Is a(33900) the last term equal to 1? No other terms with a(n) = 1 for n < 10000000.
LINKS
Robert Israel, Table of n, a(n) for n = 0..10000
Jesse Sealand, Project to manage derivative sequences.
EXAMPLE
prime(1)=2, hence a(1) = (0 + 2)/2^1 = 1;
prime(2)=3, hence a(2) = (a(1)+3)/2^2 = 1;
prime(3)=5, hence a(3) = (a(2)+5)/2^1 = 3;
prime(4)=7, hence a(4) = (a(3)+7)/2^1 = 5, etc.
MAPLE
N:= 1000: # to get N terms
T:= 0; A[0]:= T;
for n from 1 to N do
T:= T + ithprime(n);
T:= T / 2^padic[ordp](T, 2);
A[n]:= T;
od:
seq(A[n], n=0..N); # Robert Israel, Jun 01 2014
MATHEMATICA
Do[{
If[n == 1, t = 0];
t = Prime[n] + t;
k = IntegerExponent[t, 2];
t = t/(Power[2, k ]);
(* a(n)=t *)
}, {n, 1, 1000}]
(* Jesse Sealand, Aug 17 2019 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, Nov 18 2005
EXTENSIONS
Definition corrected and offset changed by N. J. A. Sloane, Sep 01 2019.
STATUS
approved