A051356 - OEIS

%I #9 Jan 18 2025 09:35:05

%S 0,5,-2,9,-4,13,-6,17,46,15,-22,19,-24,23,76,135,74,7,78,5,-74,9,98,1,

%T 102,-1,106,-3,110,-17,114,251,112,261,110,-47,-210,-43,130,309,128,

%U 319,126,323,124,-87,-310,-83,-312,-79,160,-81,170,427,690

%N Start with 0, run through primes >=5, adding if -1 mod 6, subtracting if +1 mod 6.

%H Harvey P. Dale, <a href="/A051356/b051356.txt">Table of n, a(n) for n = 0..1000</a>

%F a(n) = Sum_{k=2..n+2} A173950(k)*prime(k). - _Ridouane Oudra_, Jan 09 2025

%e a(5) = 13 = 5-7+11-13+17.

%t Accumulate[Join[{0},If[Mod[#,6]==1,-#,#]&/@Prime[Range[3,60]]]] (* _Harvey P. Dale_, Jul 23 2012 *)

%Y Cf. A173950.

%K sign,easy

%O 0,2

%A Armand Turpel armandt(AT)unforgettable.com