%I A152947
%S A152947 1,1,2,4,7,11,16,22,29,37,46,56,67,79,92,106,121,137,154,172,191,211,
%T A152947 232,254,277,301,326,352,379,407,436,466,497,529,562,596,631,667,704,
%U A152947 742,781,821,862,904,947,991,1036,1082,1129,1177,1226,1276,1327,1379
%N A152947 a(1)=1; then add 0 to the first number, then 1,2,3,4... and so on.
%C A152947 basic/fundamental/general sequence(s), similar to Triangular numbers 
               (A000217).
%F A152947 a(n) = 1+A000217(n-2) = A000124(n-2), n>1. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), 
               Jan 03 2009]
%F A152947 a(n)=n+a(n-1)-2 (with a(1)=1) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), 
               Nov 18 2009]
%e A152947 For n=2, a(2)=2+1-2=1; n=3, a(3)=3+1-2=2; n=4, a(4)=4+2-2=4; n=5, a(5)=5+4-2=7 
               [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 18 2009]
%t A152947 s=1;lst={1};Do[s+=n;AppendTo[lst,s],{n,0,5!}];lst
%o A152947 (Other) SAGE: [1+binomial(n,2) for n in xrange(0, 54)] # [From Zerinvary 
               Lajos (zerinvarylajos(AT)yahoo.com), Mar 12 2009]
%Y A152947 Cf. A000217.
%Y A152947 Sequence in context: A025732 A025739 A000124 this_sequence A098574 A005689 
               A131075
%Y A152947 Adjacent sequences: A152944 A152945 A152946 this_sequence A152948 A152949 
               A152950
%K A152947 nonn,new
%O A152947 1,3
%A A152947 Vladimir Orlovsky (4vladimir(AT)gmail.com), Dec 15 2008