A105447 Positive integers whose representation as Roman Fibonacci numbers has exactly two symbols.

4, 6, 7, 9, 10, 11, 12, 14, 15, 16, 18, 19, 20, 22, 23, 24, 26, 29, 31, 32, 33, 35, 36, 37, 39, 42, 47, 50, 52, 53, 54, 56, 57, 58, 60, 63, 68, 76, 81, 84, 86, 87, 88, 90, 91, 92, 94, 97, 102, 110, 123, 131, 139, 141, 142, 143, 145, 146, 147, 149, 152, 157

Offset

1,1

Links

Table of n, a(n) for n=1..62.

Formula

a(n) is an element of A105447 iff A105446(n) = 2. a(n) is the sum or difference of two Fibonacci numbers A000045 and a(n) is not itself a Fibonacci number A000045.

Example

In Roman Fibonacci number representation:
4 = "22", 6 = "33", 7 = "52", 9 = "81", 10 = "55", 11 = "83", 12 = "1A",
14 = "A1", 15 = "A2", 16 = "88", 18 = "3B", 19 = "2B", 20 = "1B", ...
143 = "1F", 145 = "F1", 146 = "F2", 147 = "F3", 149 = "F5", 152 = "F8".

Crossrefs

Cf. A000045, A006968, A105446, A105448-A105455.

Sequence in context: A225871 A288383 A001690 * A242286 A144222 A010414

Adjacent sequences: A105444 A105445 A105446 * A105448 A105449 A105450

Keyword

base,easy,nonn

Author

Jonathan Vos Post, Apr 09 2005

Status

approved