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 A118668 Number of distinct digits needed to write the n-th triangular number in decimal representation. 8
 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 1, 1, 2, 2, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 3, 1, 3, 3, 3, 3, 3, 3, 3, 2, 4, 3, 3, 3, 3, 4, 4, 4, 3, 4, 4, 4, 4, 2, 3, 4, 3, 4, 4, 3, 4, 2, 3, 4, 4, 4, 3, 3, 4, 3, 4, 3, 2, 4, 4, 4, 3, 3, 4, 4, 3, 4, 3, 4, 3, 4, 4, 4, 4, 3, 4, 3, 4, 4, 4, 2, 2, 3, 3, 4 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 COMMENTS 0 < a(n) <= 10; a(n) = A043537(A000217(n)). LINKS Reinhard Zumkeller, Table of n, a(n) for n = 0..10000 EXAMPLE n=99: 99*(99+1)/2 = 4950 -> a(99) = #{0,4,5,9} = 4; see A119033 for an overview of sequences with terms composed of not more than 3 distinct digits. n=100: 100*(100+1)/2 = 5050 -> a(100) = #{0,5} = 2; MATHEMATICA Length[Union[IntegerDigits[#]]]&/@Accumulate[Range[0, 110]] (* Harvey P. Dale, Jul 23 2012 *) PROG (Haskell) a118668 = a043537 . a000217 a118668_list = map a043537 a000217_list -- Reinhard Zumkeller, Jul 11 2015 CROSSREFS Cf. A000217, A043537, A045914, A213517, A213518, A255678. Sequence in context: A080972 A037814 A179529 * A273429 A273915 A270969 Adjacent sequences:  A118665 A118666 A118667 * A118669 A118670 A118671 KEYWORD nonn,base AUTHOR Reinhard Zumkeller, May 19 2006 STATUS approved

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Last modified April 17 02:18 EDT 2021. Contains 343059 sequences. (Running on oeis4.)