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%I #24 Aug 19 2021 16:25:50
%S 0,10,120,190,210,300,630,780,820,990,1540,1770,1830,2080,2850,3160,
%T 3240,3570,4560,4950,5050,5460,6670,7140,7260,7750,9180,9730,9870,
%U 10440,12090,12720,12880,13530,15400,16110,16290,17020,19110,19900,20100,20910,23220
%N Triangular numbers of the form 10*k.
%C Intersection of A000217 and A008592. - _Michel Marcus_, Sep 17 2013
%H Harvey P. Dale, <a href="/A069498/b069498.txt">Table of n, a(n) for n = 1..1000</a>
%F G.f.: -10*x^2*(x^6+11*x^5+7*x^4+2*x^3+7*x^2+11*x+1) / ((x-1)^3*(x+1)^2*(x^2+1)^2). - _Colin Barker_, Sep 23 2013
%p a[0] := 0:a[1] := 4:a[2] := 15:a[3] := 19:seq((20*(floor(i/4))+a[i mod 4])*(20*(floor(i/4))+a[i mod 4]+1)/2,i=0..100);
%t Select[Accumulate[Range[0,250]],Divisible[#,10]&] (* _Harvey P. Dale_, Aug 28 2016 *)
%Y Cf. A000217, A008592.
%K nonn,easy
%O 1,2
%A _Amarnath Murthy_, Mar 30 2002
%E Corrected and extended by _Harvey P. Dale_ and _Sascha Kurz_, Mar 31 2002
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