A292772 a(n) = cardinality of a certain set of natural numbers defined using A117818.

1, 2, 3, 4, 6, 8, 12, 18, 25, 38, 56, 89, 138, 218, 342, 547, 882, 1429, 2299, 3705, 5961, 9615, 15524, 25057, 40442, 65247, 105412, 170224, 274963, 44156, 717551, 1159406, 1873356

Offset: 0

Author

N. J. A. Sloane, Sep 29 2017

Keywords

• nonn
• more

Comments

Let s(n) = A117818(n). Define sets C_n of natural numbers by C_0 = {1}; C_(n+1) = C_n union {s(x+y): x, y in C_n} for n >= 0. Then a(n) = |C_n|.

Links

• Mihai Caragiu, P. A. Vicol, and M. Kaki, On Conway's subprime function, a covering of N and an unexpected appearance of the golden ratio, Fib. Q., 55 (2017), no. 4, 327-331.

Crossrefs

Cf. A117818.