login
A260214
a(n) is the first triangular number whose decimal representation uses n distinct digits.
2
0, 10, 105, 1035, 10296, 102378, 1024596, 10348975, 102738945, 1062489753
OFFSET
1,2
LINKS
FORMULA
a(n) = A255678(n)*(A255678(n)+1)/2.
MATHEMATICA
# (# + 1)/2 & /@ {0, 4, 14, 45, 143, 452, 1431, 4549, 14334, 46097} (* terms in A255678 *) (* Robert G. Wilson v, Jul 21 2015 *)
PROG
(PARI) number_of_distinct_digits(m) = if(m==0, 1, #vecsort(digits(m), , 8))
a(n)=my(m=0); while(!(number_of_distinct_digits(m*(m+1)/2)==n), m++); m*(m+1)/2;
first(m)=vector(m, n, a(n)) \\m<=10 /* Anders Hellström, Aug 03 2015 */
CROSSREFS
KEYWORD
nonn,base,fini,full
AUTHOR
Anders Hellström, Jul 19 2015
STATUS
approved