seq: Number of self-avoiding walks on cubic lattice with no more than n steps

[Jonathan Post]

Number of self-avoiding walks on cubic lattice with no more than n steps.

1, 7, 37, 187, 913, 4447, 21373, 102763, 490729, 2344615, 11154493,
53088643, 251931385, 1195905895, 5664817573, 26839963627,
126961839601, 600692091703, 2838415775797, 13414448995411,
63331776834145, 299041867336303, 1410823850778709, 6656812065970123

Formula
Partial sum of A001412

Offset
0,2

Example:
a(9) = 1 + 6 + 30 + 150 + 726 + 3534 + 16926 + 81390 + 387966 +
1853886 = 2344615

Comment:
Primes include a(1) = 7, a(2) = 37, a(5) = 4447, a(8) = 102763, a(15)
= 26839963627.

Cf. A001412, A002902, A078717, A001411, A001413.

Keywords:
nonn,walk

Not all partial sums are desired, but this one seems natural and
non-arbitrary to me.  Anyone find this worth submitting?

Best,

Jonathan Vos Post