A118577 - OEIS

A118577

a(1) = 1. For m >= 0 and 1 <= k <= 2^m, a(2^m +k) = number of earlier terms of the sequence which are coprime to a(k).

1, 1, 2, 3, 4, 5, 4, 6, 8, 9, 5, 8, 6, 11, 7, 6, 16, 17, 9, 13, 11, 19, 13, 11, 15, 18, 23, 17, 14, 26, 28, 14, 32, 33, 19, 26, 20, 33, 21, 15, 23, 29, 37, 26, 18, 40, 41, 19, 28, 47, 37, 46, 47, 50, 49, 50, 37, 25, 55, 57, 33, 35, 34, 34, 64, 65, 39, 51, 41, 57, 43, 31, 45, 54, 61

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OFFSET

1,3

LINKS

Table of n, a(n) for n=1..75.

EXAMPLE

8 = 2^2 + 4; so for a(8) we want the number of terms among terms a(1), a(2),... a(7) which are coprime to a(4) = 3. So a(8) = 6.

PROG

(PARI) A118577(mmax)= { local(a, ncopr); a=[1]; for(m=0, mmax, for(k=1, 2^m, ncopr=0; for(i=1, 2^m+k-1, if( gcd(a[k], a[i])==1, ncopr++; ); ); a=concat(a, ncopr); ); ); return(a); } { print(A118577(6)); } - R. J. Mathar, May 30 2006

CROSSREFS

Sequence in context: A324196 A269597 A233775 * A377070 A135681 A135680

Adjacent sequences: A118574 A118575 A118576 * A118578 A118579 A118580

KEYWORD

nonn

AUTHOR

Leroy Quet, May 24 2006

EXTENSIONS

More terms from R. J. Mathar, May 30 2006

STATUS

approved