cp's OEIS Frontend

A104613 Write the natural numbers in base 9 in a triangle with k digits in the k-th row, as shown below. Sequence gives the leading diagonal.

%I A104613 #5 Apr 23 2012 21:43:49
%S A104613 1,3,6,0,1,1,0,4,3,3,1,7,5,6,1,0,1,1,1,1,1,3,1,1,6,1,1,0,2,2,3,2,2,7,
%T A104613 2,3,2,3,3,6,3,4,2,4,4,7,5,5,3,5,5,0,6,6,6,6,7,3,7,7,1,8,8,8,1,3,0,0,
%U A104613 8,1,6,6,1,0,2,2,7,1,4,6,1,0,4,4,7,1,0,4,1,1,6,6,0,1,3,0,1,4,8,0,3,2,4,3,2
%N A104613 Write the natural numbers in base 9 in a triangle with k digits in the k-th row, as shown below. Sequence gives the leading diagonal.
%C A104613 1
%C A104613 23
%C A104613 456
%C A104613 7810
%C A104613 11121
%C A104613 314151...
%t A104613 t = Flatten[ IntegerDigits[ Range[1800], 9]]; t[[Table[n(n + 1)/2, {n, 105}]]]
%o A104613 (PARI) { pln=0; Trn = 1; Trd=1;
%o A104613 for(ixp=1, 1625, casi = ixp; cvst=0;
%o A104613 while(casi != 0, cvd = casi%9;
%o A104613 cvst=10*cvst + cvd + 1; casi = (casi - cvd) / 9 );
%o A104613 while(cvst !=0, ptch = cvst%10; pln++;
%o A104613 if(Trn==pln, print1(ptch-1, ", "); Trd++; Trn=Trn+Trd);
%o A104613 cvst = (cvst - ptch) / 10 ) ) } \\\ _Douglas Latimer_, Apr 23 2012
%Y A104613 Cf. A104606, A104607, A104608, A104609, A104610, A104611, A104612, A091425, A104614, A104615, A104616, A104617, A104618, A104619, A104620.
%K A104613 base,nonn
%O A104613 1,2
%A A104613 _Robert G. Wilson v_, Mar 16 2005