Searching the very nice web site on Integer Sequences:
http://www.research.att.com/~njas/sequences/index.html

One finds a single sequence that matches these numbers (though it starts with an additional term 1):

Search: 3, 9, 19, 33, 51

Displaying 1-1 of 1 results found. page 1
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A058331 2*n² + 1. +20
45
1, 3, 9, 19, 33, 51, 73, 99, 129, 163, 201, 243, 289, 339, 393, 451, 513, 579, 649, 723, 801, 883, 969, 1059, 1153, 1251, 1353, 1459, 1569, 1683, 1801, 1923, 2049, 2179, 2313, 2451, 2593, 2739, 2889, 3043, 3201, 3363, 3529, 3699, 3873, 4051

It is nice to look at the site - as it gives a number of places this sequence occurs, along with references etc.

Walter Whiteley
York University