A068132 Triangular numbers with sum of digits = 28.

5995, 14878, 17578, 24976, 29890, 32896, 36856, 37675, 42778, 47278, 52975, 53956, 54946, 55945, 56953, 57970, 67528, 68635, 69751, 70876, 75466, 76636, 77815, 83845, 85078, 87571, 88831, 91378, 92665, 93961, 95266, 96580, 97903

Offset

0,1

Comments

1. The sequence is unbounded, as the (10^k + 9)-th triangular number for k >1 is a term. 2. The sum of the digits of triangular numbers in most cases is a triangular number. 3. Conjecture: For every triangular number T there exist infinitely many triangular numbers with sum of digits = T.

Links

Table of n, a(n) for n=0..32.

Mathematica

Select[Accumulate[Range[500]], Total[IntegerDigits[#]]==28&] (* Harvey P. Dale, Aug 30 2015 *)

Crossrefs

Cf. A068127, A068128, A068129, A068130, A068131.

Sequence in context: A055108 A046903 A171351 * A250514 A343432 A115429

Adjacent sequences: A068129 A068130 A068131 * A068133 A068134 A068135

Keyword

base,easy,nonn

Author

Amarnath Murthy, Feb 21 2002

Extensions

More terms from Sascha Kurz, Mar 06 2002

Status

approved