OFFSET
1,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..5000
C. Kimberling, The first column of an interspersion, Fibonacci Quarterly 32 (1994), pp. 301-314.
FORMULA
Define Phi = (1+sqrt(5))/2, then a(1) = 1, a(2*n) = 2*floor(n*Phi) + 2*n, a(2*n+1) = 2*floor(n*Phi) + 2*n + 2.
a(n) = A199535(n, n). - G. C. Greubel, Jun 22 2022
MATHEMATICA
a[n_]:= If[Mod[n, 2]==0, 2*Floor[(n/2)*GoldenRatio] +n, 2*Floor[(n-1)/2*GoldenRatio] +n+1] -Boole[n==1];
Table[a[n], {n, 80}] (* G. C. Greubel, Jun 22 2022 *)
PROG
(SageMath)
def A199536(n):
if (n==1): return 1
elif (n%2==0): return 2*floor(n*golden_ratio/2) + n
else: return 2*floor((n-1)*golden_ratio/2) +n+1
[A199536(n) for n in (1..80)] # G. C. Greubel, Jun 22 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
Casey Mongoven, Nov 07 2011
STATUS
approved