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 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Anders Hellström, Table of n, a(n) for n = 1..10 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 Cf. A000217, A043537, A118668, A255678. Sequence in context: A360276 A210136 A068093 * A077369 A068618 A096484 Adjacent sequences: A260211 A260212 A260213 * A260215 A260216 A260217 KEYWORD nonn,base,fini,full AUTHOR Anders Hellström, Jul 19 2015 STATUS approved

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Last modified October 4 16:17 EDT 2023. Contains 365887 sequences. (Running on oeis4.)