The next term is too large to include.
Table of n, a(n) for n=1..7.
OEIS Wiki, Simplicial polytopic numbers
56 is the 6th 3-simplex (or tetrahedral) number = A000292(6).
55525372 is the 56th 6-simplex number = A000579(61).
The next term will be the 55525372th 56-simplex number.
Cf. A000217, A000292, A000579.
Sequence in context: A060631 A275487 A096100 * A195694 A021451 A210188
Adjacent sequences: A260158 A260159 A260160 * A260162 A260163 A260164
Robin Powell, Nov 09 2015