OFFSET
1,4
LINKS
Clark Kimberling, Table of n, a(n) for n = 1..1000
EXAMPLE
gcd(15,3) = 3, gcd(14,2) = 2, gcd(13,1) = 1, so that a(4) = 3.
MATHEMATICA
b[n_] := 2^n; c[n_] := n;
Table[m = 1; While[GCD[b[n] - m, c[n] - m] != 1, m++]; m, {n, 1, 140}]
rp[n_]:=Module[{m=1, n2=2^n}, While[!CoprimeQ[n2-m, n-m], m++]; m]; Array[ rp, 100] (* Harvey P. Dale, Feb 13 2021 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Jul 26 2012
STATUS
approved