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A100792
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Group the natural numbers so that the n-th group contains n(n+1)/2 = T(n) terms: (1), (2,3,4), (5,6,7,8,9,10), (11,12,13,14,15,16,17,18,19,20),(21,22,23,24,25,26,27,28,29,30,31,32,33,34,35),... The r-th term of the n-th row of the following triangle is the sum of the next r terms of the n-th group, e.g. third row is (5),(6+7), (8+9+10) or 5,13,27. Sequence contains the triangle read by rows.
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%I #4 Dec 05 2013 19:56:59
%S 1,2,7,5,13,27,11,25,45,74,21,45,75,114,165,36,75,120,174,240,321,57,
%T 117,183,258,345,447,567,85,173,267,370,485,615,763,932,121,245,375,
%U 514,665,831,1015,1220,1449,166,335,510,694,890,1101,1330,1580,1854,2155
%N Group the natural numbers so that the n-th group contains n(n+1)/2 = T(n) terms: (1), (2,3,4), (5,6,7,8,9,10), (11,12,13,14,15,16,17,18,19,20),(21,22,23,24,25,26,27,28,29,30,31,32,33,34,35),... The r-th term of the n-th row of the following triangle is the sum of the next r terms of the n-th group, e.g. third row is (5),(6+7), (8+9+10) or 5,13,27. Sequence contains the triangle read by rows.
%e 1
%e 2 7
%e 5 13 27
%e 11 25 45 74
%e 21 45 75 114 165
%e ...
%Y Cf. A100791.
%K easy,nonn,tabl
%O 1,2
%A _Amarnath Murthy_, Dec 01 2004
%E More terms from _Ray Chandler_, Dec 10 2004
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