cp's OEIS Frontend

A252729 Start with 1, add 1, subtract 2, multiply by 3, add 4, subtract 5, multiply by 6, add 7, etc.

%I A252729 #16 Sep 29 2024 21:09:50
%S A252729 1,2,0,0,4,-1,-6,1,-7,-63,-53,-64,-768,-755,-769,-11535,-11519,-11536,
%T A252729 -207648,-207629,-207649,-4360629,-4360607,-4360630,-104655120,
%U A252729 -104655095,-104655121,-2825688267,-2825688239,-2825688268,-84770648040,-84770648009
%N A252729 Start with 1, add 1, subtract 2, multiply by 3, add 4, subtract 5, multiply by 6, add 7, etc.
%H A252729 Harvey P. Dale, <a href="/A252729/b252729.txt">Table of n, a(n) for n = 1..1000</a>
%p A252729 A252729 := proc(n)
%p A252729     option remember;
%p A252729     if n =1 then
%p A252729         1;
%p A252729     elif modp(n,3) = 2 then
%p A252729         procname(n-1)+n-1;
%p A252729     elif modp(n,3) = 0 then
%p A252729         procname(n-1)-(n-1);
%p A252729     elif modp(n,3) = 1 then
%p A252729         procname(n-1)*(n-1);
%p A252729     fi ;
%p A252729 end proc:
%p A252729 seq(A252729(n),n=1..32) ; # _R. J. Mathar_, Mar 20 2015
%t A252729 nxt[{n_,a_}]:={n+1,Which[Mod[n+1,3]==1,a+n+1,Mod[n+1,3]==2,a-(n+1),True, a*(n+1)]}; Transpose[NestList[nxt,{0,1},35]][[2]] (* _Harvey P. Dale_, Mar 29 2015 *)
%o A252729 (Liberty BASIC)
%o A252729 input "How many terms? ";nt:a=1
%o A252729 1 print a;",";:n=n+1:a=a+n
%o A252729 print a;",";:n=n+1:a=a-n
%o A252729 print a;",";:n=n+1:a=a*n
%o A252729 if n<nt then goto 1 else end
%K A252729 sign,easy
%O A252729 1,2
%A A252729 _Edwin McCravy_, Dec 20 2014