OFFSET
0,3
COMMENTS
The T(k) for each n are at A118389.
LINKS
T. D. Noe, Table of n, a(n) for n = 0..10000
EXAMPLE
====================
n k T(k)
====================
0 0 0
1 1 1
2 6 21
3 2 3
4 9 45
5 5 15
6 3 6
7 12 78
8 7 28
9 13 91
10 4 10
MATHEMATICA
nn = 68; t = Table[0, {nn}]; n = 0; found = 0; While[found < nn, n++; k = n (n + 1)/2; d = IntegerDigits[k]; s = Sort[FromDigits /@ Flatten[Table[Partition[d, i, 1], {i, Length[d]}], 1]]; i = 1; While[i <= Length[s] && s[[i]] <= nn, If[t[[s[[i]]]] == 0, t[[s[[i]]]] = n; found++]; i++]]; t = Join[{0}, t] (* T. D. Noe, Sep 03 2013 *)
Module[{tn=Accumulate[Range[200]], trms}, trms=Table[SelectFirst[ tn, SequenceCount[ IntegerDigits[ #], IntegerDigits[n]]>0&], {n, 70}]; Join[ {0}, (Sqrt[8#+1]-1)/2&/@trms]] (* Harvey P. Dale, Aug 02 2021 *)
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Jonathan Vos Post, Apr 26 2006
EXTENSIONS
Corrected by T. D. Noe, Sep 03 2013
STATUS
approved