%I A083392
%S A083392 0,1,2,4,6,9,12,16,20,25,30,36,42,49,56,64,72,81,90,100,110,121,132,144,
%T A083392 156,169,182,196,210,225,240,256,272,289,306,324,342,361,380,400,420,441,
%U A083392 462,484,506,529,552,576,600,625,650,676,702
%V A083392 0,-1,2,-4,6,-9,12,-16,20,-25,30,-36,42,-49,56,-64,72,-81,90,-100,110,
%W A083392 -121,132,-144,156,-169,182,-196,210,-225,240,-256,272,-289,306,-324,342,
%X A083392 -361,380,-400,420,-441,462,-484,506,-529,552,-576,600,-625,650,-676,702
%N A083392 Alternating partial sums of A000217.
%F A083392 Sum{i=0, n, (-1)^i*t(i)} where t(i)=i*(i+1)/2
%e A083392 a(4)=t(0)-t(1)+t(2)-t(3)+t(4)=0-1+3-6+10=6
%o A083392 (PARI) t(n)=n*(n+1)/2 for (n=0,30,print1(sum(i=0,n,(-1)^i*t(i))","))
%Y A083392 Cf. A000217, A002620.
%Y A083392 Sequence in context: A075354 A086378 A088900 this_sequence A076921 A002620 
               A087811
%Y A083392 Adjacent sequences: A083389 A083390 A083391 this_sequence A083393 A083394 
               A083395
%K A083392 sign
%O A083392 0,3
%A A083392 Jon Perry (perry(AT)globalnet.co.uk), Jun 11 2003
%E A083392 More terms from David W. Wilson, Jun 14 2003