A117464 Triangular numbers for which the product of the digits is a square.

0, 1, 10, 28, 55, 66, 91, 105, 120, 190, 210, 300, 406, 595, 630, 703, 780, 820, 903, 990, 1035, 1081, 1128, 1326, 1540, 1770, 1830, 2016, 2080, 2211, 2346, 2701, 2850, 3003, 3081, 3160, 3240, 3403, 3486, 3570, 4005, 4095, 4560, 4950, 5050, 5151, 5460, 5995

Offset

0,3

Links

Table of n, a(n) for n=0..47.

Example

3486 is in the sequence because (1) it is a triangular number and (2) the product of its digits 3*4*8*6=576 is a square.

Mathematica

Select[Accumulate[Range[0, 150]], IntegerQ[Sqrt[Times@@IntegerDigits[#]]]&] (* Harvey P. Dale, Jul 21 2016 *)

Crossrefs

Cf. A000217.

Sequence in context: A069953 A113746 A177720 * A081273 A060544 A088406

Adjacent sequences: A117461 A117462 A117463 * A117465 A117466 A117467

Keyword

base,nonn

Author

Luc Stevens (lms022(AT)yahoo.com), Apr 26 2006

Status

approved