A217929 Number of sequences of n 2's and 3's with curling number 2, which have the form XY^2 with Y = 2, and which are robust.

0, 0, 1, 2, 4, 7, 16, 30, 63, 122, 251, 495, 1003, 1990, 4012, 7992, 16043, 32024, 64173, 128226, 256692, 513131, 1026765, 2053034, 4107060, 8213109, 16428221, 32854454, 65712883, 131421763, 262851530, 525695069, 1051406116

Offset

1,4

Comments

Let S be a sequence of n 2's and 3's with curling number 2 and which has the form XY^2 with Y = 2. S is robust if no proper suffix of S^3 has curling number > 2.

Links

Table of n, a(n) for n=1..33.

Index entries for sequences related to curling numbers

Crossrefs

Cf. A217832, A217930.

Sequence in context: A026731 A026764 A027230 * A320465 A345333 A259544

Adjacent sequences: A217926 A217927 A217928 * A217930 A217931 A217932

Keyword

nonn

Author

N. J. A. Sloane, Oct 15 2012

Status

approved