Superseeker error?

[N. J. A. Sloane]

There is no error.  Creighton, you submitted this sequence:
[ 0,1,3,10,36,133,495,1846,6888,25705,95931,358018,1336140]
Here are the first, second and third differences:
> DIFF(%);                                                        
                 [1, 2, 7, 26, 97, 362, 1351, 5042, 18817, 70226, 262087, 978122]

> DIFF(%);
                   [1, 5, 19, 71, 265, 989, 3691, 13775, 51409, 191861, 716035]

> DIFF(%);
                    [4, 14, 52, 194, 724, 2702, 10084, 37634, 140452, 524174]
The latter sequence does match A003500, just
as Superseeker says:

Transformation T020 gave a match with:
%I A003500 M1278
%S A003500 2,4,14,52,194,724,2702,10084,37634,140452,524174,1956244,7300802,
%T A003500 27246964,101687054,379501252,1416317954,5285770564,19726764302,
%U A003500 73621286644,274758382274,1025412242452,3826890587534,14282150107684
%N A003500 a(n) = 4a(n-1) - a(n-2).
...

NJAS