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 A119037 Triangular numbers composed of digits {0,1,4}. 2

%I

%S 1,10,10011,10440,41041,41001040,141044410,1010004040,4104044101,

%T 14041444410,114011410040100,440404440401100,1041401040044401,

%U 40114114410110140,14001400401400441011,1040410404040110411004140

%N Triangular numbers composed of digits {0,1,4}.

%H G. Resta, <a href="http://www.numbersaplenty.com/tr/tr014.html">Tridigital Triangular Numbers</a>

%t Rest[Select[FromDigits/@Tuples[{0, 1, 4}, 12], IntegerQ[(Sqrt[8 # + 1] - 1)/2] &]] (* _Vincenzo Librandi_, Dec 18 2015 *)

%o (MAGMA) [t: n in [1..2*10^7] | Set(Intseq(t)) subset {0,1,4} where t is n*(n+1) div 2]; // _Vincenzo Librandi_, Dec 18 2015

%Y Cf. A000217, A058414, A119038. See A119033 for a table of cross-references.

%K nonn,base

%O 1,2

%A _Giovanni Resta_, May 10 2006

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Last modified December 7 00:09 EST 2019. Contains 329812 sequences. (Running on oeis4.)