Spiro-Fibonacci numbers

[Neil Fernandez]

Write terms in square boxes, working in a spiral, cf. Ulam prime spiral,
such that a(n) = sum of the two previous terms written closest to the
box for a(n).

(See Wai Ha Lee's A063826 for movements in Ulam prime spiral).

The Spiro-Fibonacci sequence runs:

0, 1, 1, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
16, 18, 21, 24, 27, 31, 36, 42, 48, 54, 61, 69, 78, 88, 98, 108, 119,
131, 144, 158, 172, 186, 201, 217, 235, 256, 280, 304, 328, 355, 386,
422, 464, 512, 560, 608, 662, 723, 792, 870, 958, 1056, 1154, 1252,
1360, 1479, 1610, 1754, 1912, 2084, 2256, 2428, 2614, 2815, 3032, 3267,
3523, 3803, 4107, 4411, 4715, 5043, 5398, 5784, 6206, 6670, 7182, 7742,
8302, 8862, 9470, 10132, 10855, 11647, 12517, 13475, 14531, 15685,
16839, 17993, 19245, 20605, 22084, 23694, 25448, 27360, 29444, 31700,
33956, 36212, 38640, 41254, 44069, 47101, 50368, 53891, 57694, 61801,
66212, 70623, 75034, 79749, 84792, 90190, 95974, 102180, 108850, 116032,
123774, 132076, 140378, 148680, 157542, 167012, 177144, 187999, 199646,
212163, 225638, 240169, 255854, 272693, 289532, 306371, 324364, 343609,
364214, 386298, 409992, 435440, 462800, 492244, 523944, 557900, 591856,
625812, 662024, 700664, 741918, 785987, 833088, 883456, 937347, 995041,
1056842, 1123054, 1193677 

Prime terms run:

2, 3, 5, 7, 11, 13, 31, 61, 119, 131, 12517, 53891, 240169, 272693,
1409957, 15776993

Neil

-- 
Neil Fernandez