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A100721
a(n) = n - a(a(a(a(a(a(n-1)))))), a(1)=1.
2
1, 1, 2, 3, 4, 5, 6, 7, 7, 8, 8, 9, 10, 10, 11, 12, 13, 13, 14, 15, 16, 17, 17, 18, 19, 20, 21, 22, 22, 23, 24, 25, 26, 27, 28, 28, 29, 30, 31, 32, 33, 34, 34, 35, 35, 36, 37, 38, 39, 40, 41, 41, 42, 42, 43, 44, 44, 45, 46, 47, 48, 49, 50, 50, 51, 51, 52, 53, 53, 54, 55, 56, 56, 57, 58, 59
OFFSET
1,3
LINKS
Pierre Letouzey, Shuo Li, and Wolfgang Steiner, Pointwise order of generalized Hofstadter functions G, H and beyond, arXiv:2410.00529 [cs.DM], 2024. See p. 1.
MAPLE
H:=proc(n) option remember; if n=1 then 1 else n-H(H(H(H(H(H(n-1)))))); fi; end proc;
MATHEMATICA
a[1]= 1; a[n_]:= a[n]= n - a[a[a[a[a[a[n-1]]]]]]; Table[ a[n], {n, 75}] (* Robert G. Wilson v, Dec 16 2004 *)
PROG
(SageMath)
@CachedFunction # a = A100721
def a(n): return 1 if (n==1) else n - a(a(a(a(a(a(n-1))))))
[a(n) for n in range(1, 100)] # G. C. Greubel, Nov 16 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Dec 12 2004
STATUS
approved