

A104620


Consider the presentation of the digits of the natural numbers in a triangular form for successive bases, b. Now examine the main diagonal of these triangles and note the first occurrence of the n digits (0 through b1). This is its own triangle presented here.


15



1, 2, 1, 4, 1, 9, 6, 1, 8, 2, 3, 1, 4, 2, 19, 10, 1, 7, 2, 5, 31, 8, 1, 6, 2, 10, 18, 3, 14, 1, 7, 2, 11, 12, 3, 10, 4, 1, 29, 2, 8, 13, 3, 12, 62, 13, 1, 5, 2, 12, 6, 3, 9, 23, 73, 12, 1, 9, 2, 13, 11, 3, 16, 7, 80, 4, 22, 1, 8, 2, 6, 15, 3, 18, 19, 10, 4, 37, 11, 1, 9, 2, 13, 70, 3, 7, 26, 16
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OFFSET

1,2


COMMENTS

See A104606 through A104613, A091425, A104614 through A104619 as examples in the OEIS data base for triangular forms to base n>1.
t(n,2)=1, t(n,4)=2, t(n,7)=3, t(n,11)=4, t(n,16)=5 and t(n,1+i(i+1)/2)=i.


LINKS

Table of n, a(n) for n=1..88.


EXAMPLE

Triangle begins:
1
2 1
4 1 9
6 1 8 2
3 1 4 2 19
10 1 7 2 5 31


MATHEMATICA

f[n_] := If[n == 1, 0, Block[{t = Flatten[ IntegerDigits[ Range[ 2000], n]]}, u = t[[ Table[ i(i + 1)/2, {i, 100}]]]; Table[ Position[u, i, 1, 1], {i, 0, n  1}]]]; Flatten[ Table[ f[n], {n, 13}]]


CROSSREFS

Cf. A104606, A104607, A104608, A104609, A104610, A104611, A104612, A104613, A091425, A104614, A104615, A104616, A104617, A104618, A104619.
Sequence in context: A147080 A146418 A146011 * A243913 A186724 A145930
Adjacent sequences: A104617 A104618 A104619 * A104621 A104622 A104623


KEYWORD

base,nonn,tabl


AUTHOR

Robert G. Wilson v, Mar 17 2005


STATUS

approved



