cp's OEIS Frontend

A114751 The following triangle contains n consecutive numbers beginning from n in ascending order if n is odd else in descending order. Sequence contains the triangle by rows.

%I A114751 #19 Aug 19 2019 04:02:00
%S A114751 1,3,2,3,4,5,7,6,5,4,5,6,7,8,9,11,10,9,8,7,6,7,8,9,10,11,12,13,15,14,
%T A114751 13,12,11,10,9,8,9,10,11,12,13,14,15,16,17,19,18,17,16,15,14,13,12,11,
%U A114751 10,11,12,13,14,15,16,17,18,19,20,21,23,22,21,20,19,18,17,16,15,14,13,12
%N A114751 The following triangle contains n consecutive numbers beginning from n in ascending order if n is odd else in descending order. Sequence contains the triangle by rows.
%F A114751 a(n) = (3*t+2-t*(-1)^(t-1))/2-(1+(-1)^t)*(j-1)/2+(1-(-1)^t)*(j-1)/2, where j = (t*t+3*t+4)/2-n, t=floor((-1+sqrt(8*n-7))/2). - _Boris Putievskiy_, Jan 30 2013
%e A114751 1
%e A114751 3 2
%e A114751 3 4 5
%e A114751 7 6 5 4
%e A114751 5 6 7 8 9
%e A114751 11 10 9 8 7 6
%e A114751 ...
%p A114751 for n from 1 to 14 do if n mod 2 = 1 then print(seq(k,k=n..2*n-1)) else print(seq(2*n-k,k=1..n)) fi od; # yields sequence in triangular form # _Emeric Deutsch_, Jan 26 2006
%Y A114751 Cf. A114752, A114753, A210530.
%K A114751 easy,nonn,tabl
%O A114751 1,2
%A A114751 _Amarnath Murthy_, Nov 15 2005
%E A114751 More terms from _Emeric Deutsch_, Jan 26 2006