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A118982
a(1)=1. For m>=0 and 1<=k<=2^m, a(2^m +k) = number of earlier terms of the sequence that are coprime to k.
1
1, 1, 2, 2, 4, 2, 6, 2, 8, 2, 9, 3, 12, 2, 14, 4, 16, 4, 14, 4, 20, 2, 20, 4, 20, 4, 26, 2, 27, 5, 21, 7, 32, 8, 28, 8, 32, 4, 33, 9, 32, 9, 41, 5, 43, 12, 31, 15, 48, 8, 50, 13, 36, 16, 54, 9, 49, 18, 42, 16, 60, 8, 61, 20, 64, 20, 48, 20, 57, 11, 63, 23, 51, 22, 71, 14, 74, 22, 47, 27
OFFSET
1,3
EXAMPLE
Since 16 = 2^3 +8, a(16) equals the number of terms among (a(1),a(2),...a(15)) that are coprime to 8. Since the terms 1,1,9 and 3 are the only earlier terms coprime to 8, a(16) = 4.
MAPLE
A118982 := proc(nmax) local a, m, k, an, i; a := [1] ; m := 0 ; while 2^m <= nmax do for k from 1 to 2^m do an := 0 ; for i from 1 to nops(a) do if gcd(k, a[i]) = 1 then an := an +1 ; fi ; od ; a := [op(a), an] ; od ; m := m+1 ; od ; RETURN(a) ; end: an := A118982(100) : for n from 1 to nops(an) do printf("%d, ", an[n]) ; od ; # R. J. Mathar, Aug 06 2006
CROSSREFS
Sequence in context: A080221 A137849 A316440 * A129457 A275365 A119655
KEYWORD
nonn
AUTHOR
Leroy Quet, May 25 2006
EXTENSIONS
More terms from R. J. Mathar, Aug 06 2006
STATUS
approved