%I A061352
%S A061352 1,2,6,7,5,6,8,9,5,6,6,7,1,2,0,1,3,4,0,1,1,2,6,7,5,6,8,9,5,6,6,7,1,2,0,
%T A061352 1,3,4,0,1,1,2,6,7,5,6,8,9,5,6,6,7,1,2,0,1,3,4,0,1,1,2,6,7,5,6,8,9,5,6,
%U A061352 6,7,1,2,0,1,3,4,0,1,1,2,6,7,5,6,8,9,5,6,6,7,1,2,0,1,3,4,0,1,1,2,6,7,5
%N A061352 First row of array shown below.
%C A061352 Least significant digit of the n-th triangular number if n is odd.
%F A061352 a(1)=1; if n odd, a(n+1)=(a(n)+1) mod 10; if n even, a(n+1)=(a(n)+2n) 
               mod 10.
%F A061352 a(2n-1) = n*(2n-1)- 10*Floor[n*(2n-1)/10], a(2n) = n(2n+1)- 10*Floor[n*(2n+1)/
               10] + 1.
%e A061352 1 2 6 7 5 6 8 9 5 ...
%e A061352 3 5 8 4 7 7 0 4 ...
%e A061352 4 9 3 8 6 1 3 ...
%e A061352 0 2 9 5 2 2 ...
%e A061352 1 0 4 3 1 ...
%e A061352 1 3 4 0 ...
%Y A061352 Cf. A061353.
%Y A061352 Sequence in context: A065488 A016591 A021793 this_sequence A039926 A035569 
               A140132
%Y A061352 Adjacent sequences: A061349 A061350 A061351 this_sequence A061353 A061354 
               A061355
%K A061352 nonn,easy
%O A061352 1,2
%A A061352 Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Apr 28 2001
%E A061352 More terms and formula from Larry Reeves (larryr(AT)acm.org), May 15 
               2001