Trimorphic Number

A number $n$ such that the last digits of $n^3$ are the same as $n$. 49 is trimorphic since $49^3=117649$ (Wells 1986, p. 124). The first few are 1, 4, 5, 6, 9, 24, 25, 49, 51, 75, 76, 99, 125, 249, 251, 375, 376, 499, ... (Sloane's A033819).

See also Automorphic Number, Narcissistic Number, Super-3 Number

References

Sloane, N. J. A. Sequence A033819 in ``The On-Line Version of the Encyclopedia of Integer Sequences.'' http://www.research.att.com/~njas/sequences/eisonline.html.

Wells, D. The Penguin Dictionary of Curious and Interesting Numbers. Middlesex, England: Penguin Books, 1986.