A075558 - OEIS

%I #17 Dec 08 2024 04:00:50

%S 4,8,18,12,24,25,28,14,51,48,16,85,36,104,44,66,125,146,84,56,174,96,

%T 64,185,39,165,34,68,143,72,252,203,114,38,190,189,120,446,88,132,490,

%U 410,69,50,100,249,312,535,108,54,341,168,297,290,688,186,455,335,198,413

%N a(n) is the least composite number that has not yet appeared such that the n-th partial sum is a multiple of the n-th prime.

%H Robert Israel, <a href="/A075558/b075558.txt">Table of n, a(n) for n = 1..10000</a>

%p s:= 0: Cands:= remove(isprime, [$4..1000]): nC:= nops(Cands):

%p R:= NULL: s:= 0: p:= 1:

%p for n from 1 do

%p   p:= nextprime(p);

%p   found:= false;

%p   for i from 1 to nC do

%p     if s + Cands[i] mod p = 0 then

%p        R:= R, Cands[i];

%p        s:= s + Cands[i];

%p        Cands:= subsop(i=NULL,Cands);

%p        nC:= nC-1;

%p        found:= true;

%p        break

%p      fi

%p   od;

%p   if not found then break fi

%p od:

%p R;

%Y Cf. A002808 (composite numbers).

%K nonn,look

%O 1,1

%A _Amarnath Murthy_, Sep 24 2002

%E More terms from _Ray Chandler_, Oct 25 2003

%E Name changed by _Robert Israel_, Dec 07 2024