

A359050


a(n) is the least k such that fusc(k) + fusc(k+1) = n, where "fusc" is Stern's diatomic series (A002487).


2



0, 1, 2, 4, 5, 16, 9, 10, 17, 19, 18, 22, 21, 34, 36, 46, 38, 37, 41, 94, 42, 70, 69, 76, 75, 73, 77, 133, 74, 82, 86, 139, 137, 85, 141, 157, 138, 268, 162, 148, 146, 289, 150, 154, 182, 166, 149, 283, 165, 169, 276, 274, 281, 637, 170, 292, 282, 307, 314
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OFFSET

1,3


COMMENTS

This sequence is well defined:
 a(1) = 0,
 for any n > 1, 1/(n1) is in reduced form, so fusc(k) = 1 and fusc(k+1) = n1 for some k, and a(n) <= k.


LINKS



FORMULA



EXAMPLE

The first terms are:
n a(n) fusc(a(n)) fusc(a(n)+1)
   
1 0 0 1
2 1 1 1
3 2 1 2
4 4 1 3
5 5 3 2
6 16 1 5
7 9 4 3
8 10 3 5
9 17 5 4
10 19 7 3


PROG

(PARI) See Links section.
(Python)
f, g, k = 0, 1, 0
while f+gn:
k += 1
m, a = k+1, [1, 0]
while m:
a[m&1] = sum(a)
m >>=1
f, g = g, a[1]


CROSSREFS



KEYWORD



AUTHOR



STATUS

approved



