login
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.
15
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, 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, 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
OFFSET
1,2
COMMENTS
1
23
456
7810
11121
314151...
MATHEMATICA
t = Flatten[ IntegerDigits[ Range[1800], 9]]; t[[Table[n(n + 1)/2, {n, 105}]]]
PROG
(PARI) { pln=0; Trn = 1; Trd=1;
for(ixp=1, 1625, casi = ixp; cvst=0;
while(casi != 0, cvd = casi%9;
cvst=10*cvst + cvd + 1; casi = (casi - cvd) / 9 );
while(cvst !=0, ptch = cvst%10; pln++;
if(Trn==pln, print1(ptch-1, ", "); Trd++; Trn=Trn+Trd);
cvst = (cvst - ptch) / 10 ) ) } \\\ Douglas Latimer, Apr 23 2012
KEYWORD
base,nonn
AUTHOR
Robert G. Wilson v, Mar 16 2005
STATUS
approved