OFFSET
1,12
LINKS
Altug Alkan, Table of n, a(n) for n = 1..32768
Altug Alkan, Line plot of a(n) for n <= 2^17
Rémy Sigrist, C++ program for A317854
FORMULA
abs(a(n)) = A317742(n).
MAPLE
t:= proc(n) option remember; `if`(n<3, 1,
n -t(t(n-1)) -t(n-t(n-1)))
end:
b:= proc(n) option remember; `if`(n<3, 1,
n -b(t(n)) -b(n-t(n)))
end:
seq(2*b(n)-n, n=1..100); # after Alois P. Heinz at A317686
MATHEMATICA
t[1]=t[2]=1; t[n_] := t[n] = n - t[t[n-1]] - t[n - t[n-1]]; b[1]=b[2]=1; b[n_] := b[n] = n - b[t[n]] - b[n - t[n]]; a[n_] := 2*b[n] - n; Array[a, 95] (* Giovanni Resta, Aug 14 2018 *)
PROG
(PARI) t=vector(99); t[1]=t[2]=1; for(n=3, #t, t[n] = n-t[n-t[n-1]]-t[t[n-1]]); b=vector(99); b[1]=b[2]=1; for(n=3, #b, b[n] = n-b[t[n]]-b[n-t[n]]); vector(99, k, 2*b[k]-k)
(C++) See Links section.
CROSSREFS
AUTHOR
Altug Alkan, Aug 09 2018
STATUS
approved