A120326 Cumulative sum of the remainders when dividing primes by 3.

2, 2, 4, 5, 7, 8, 10, 11, 13, 15, 16, 17, 19, 20, 22, 24, 26, 27, 28, 30, 31, 32, 34, 36, 37, 39, 40, 42, 43, 45, 46, 48, 50, 51, 53, 54, 55, 56, 58, 60, 62, 63, 65, 66, 68, 69, 70, 71, 73, 74, 76, 78, 79, 81, 83, 85, 87, 88, 89, 91, 92, 94, 95, 97, 98, 100, 101, 102, 104, 105

Offset: 1

Author

Joost de Winter, Aug 27 2006

Keywords

• nonn

Comments

Partial sums of A039701. - Michel Marcus, Jan 21 2015

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A039701 (prime(n) mod 3).

Programs

Mathematica

s=0;lst={};Do[p=Prime[n];m=Mod[p,3];a=(p-m)/3;AppendTo[lst,s+=m],{n,3*4!}];lst (* Vladimir Joseph Stephan Orlovsky, May 24 2009 *)
Accumulate[Mod[Prime[Range[80]],3]] (* Harvey P. Dale, Sep 17 2016 *)

Formula

a(n) = sum_{k=1..n} (prime(k) mod 3).