Pattern Recognition - 148

Find out the next two numbers in the series.

 1 , 6 , 15 ,  28 , _ , _ , ..........................................

Answer

 1 ,     6 ,       15 ,      28 , _ , _ , ..........................................

 1, 3 , 6 , 10, 15, 21,  28, 36 ,45 ,55,66 ......................

Every other number from triangular series

Next two numbers  45 ,66

 1 ,     6 ,       15 ,      28 ,    45 ,  66 , ..........................................