A147561 Number of representations of n in the Fibonacci-squared base system. The columns are ..., 64, 25, 9, 4, 1, 1 = ..., 8^2, 5^2, 3^2, 2^2, 1^2, 1^2, i.e., the Fibonacci numbers A000045 squared. The 'digits' are 0, 1 or 2.
2, 3, 2, 2, 2, 3, 2, 2, 3, 5, 5, 3, 2, 2, 3, 2, 2, 3, 5, 5, 3, 2, 2, 3, 3, 4, 5, 5, 4, 3, 3, 2, 2, 3, 5, 5, 3, 2, 2, 3, 2, 2, 3, 5, 5, 3, 2, 2, 3, 3, 4, 5, 5, 4, 3, 3, 2, 2, 3, 5, 5, 3, 2, 3, 5, 5, 4, 5, 7, 8, 5, 4, 5, 8, 7, 5, 4, 5, 5, 3, 2, 3, 5, 5, 3, 2, 2, 3, 3, 4, 5, 5, 4, 3, 3, 2, 2, 3, 5, 5
Offset: 1
Examples
a(2) = 3 since 2 is 02, 20 and 11 using both columns labeled 1; a(10) = 5 because 10 = 9 + 1 with 2 Fib-sq reps 1010, 1001; 10 = 2*4 + 2 with 3 Fib-sq reps 220, 211 and 202; so there are in total 5 Fib-sq representations for 10.
Links
- David A. Corneth, Table of n, a(n) for n = 1..10000
- Ron Knott, Fibonacci Bases: The Fibonacci^2 Base System
Programs
-
PARI
first(n) = {my(fib2list = List(), fib2 = 1, t = 1, res = vector(n)); while(fib2 <= n, listput(fib2list, fib2); t++; fib2 = fibonacci(t)^2); for(i=1,3^#fib2list-1, b = digits(i,3); b = concat(vector(#fib2list-#b),b); s = sum(i=1,#b, b[i]*fib2list[i]); if(s<=n, res[s]++));res} \\ David A. Corneth, Jul 24 2017
Comments