A272639 Numbers n such that the sequence defined by {b(1)=1, b(2)=n, b(k) = squarefree part of b(k-1)+b(k-2) for k>2} does not eventually merge with the period-6 sequence A272636.

79, 83, 92, 101, 176, 258, 425, 445, 518, 679, 733, 758, 839, 932, 1272, 1311, 1382, 1432, 1453, 1454, 1495, 1899, 1904, 1991, 2207, 2317, 2444, 2450, 2570, 2609, 2733, 2736, 2773, 2783, 2961, 3038, 3076, 3166, 3291, 3370, 3384, 3416, 3456, 3473, 3539, 3545

Offset: 1

Author

N. J. A. Sloane, May 05 2016

Keywords

• nonn

Comments

The sequences b(n) for the initial terms 79, 83, 92, 101, 176, 258, 425, 445 all merge with the period-43 sequence A272637. In fact for n=83 b(n) IS A272637.

From Lars Blomberg, Jan 02 2018: (Start)

Among the first 10000 terms, two additional cycles appear:

A) with period 22: [15, 2162, 2177, 4339, 181, 1130, 1311, 2441, 938, 3379, 4317, 481, 4798, 5279, 10077, 3839, 71, 3910, 3981, 7891, 742, 8633].

B) with period 26: [23, 1801, 114, 1915, 2029, 986, 335, 1321, 46, 1367, 157, 381, 538, 919, 1457, 66, 1523, 1589, 778, 263, 1041, 326, 1367, 1693, 85, 1778].

The first occurrence of cycle A is n=28243, for cycle B n=21245.

Cycle A occurs for 17 terms, B for 24 terms and A272637 for the remaining 9959 terms. (End)

Links

• Lars Blomberg, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A007913, A272636, A272637, A272638.

Extensions

Terms a(9) and beyond from Lars Blomberg, Jan 02 2018