A157806 Absolute value of the difference between numerator and denominator of fractions arranged by Cantor's ordering (1/1, 2/1, 1/2, 1/3, 3/1, 4/1, 3/2, 2/3, 1/4, 1/5, 5/1, 6/1, ...) with equivalent fractions removed.

0, 1, 1, 2, 2, 3, 1, 1, 3, 4, 4, 5, 3, 1, 1, 3, 5, 6, 2, 2, 6, 7, 5, 1, 1, 5, 7, 8, 4, 4, 8, 9, 7, 5, 3, 1, 1, 3, 5, 7, 9, 10, 2, 2, 10, 11, 9, 7, 5, 3, 1, 1, 3, 5, 7, 9, 11, 12, 8, 4, 4, 8, 12, 13, 11, 7, 1, 1, 7, 11, 13, 14, 10, 6, 2, 2, 6, 10, 14, 15, 13, 11

Offset

0,4

Links

Andrew Howroyd, Table of n, a(n) for n = 0..10000

Prog

(PARI) seq(n)={my(L=List(), r=1, k=1); while(#L<=n, if(k==r, r++; k=0); k++; if(gcd(k, r-k)==1, listput(L, abs(r-2*k)))); Vec(L)} \\ Andrew Howroyd, Feb 03 2021

Crossrefs

Sum of numerator and denominator is given by A038567.

Sequence in context: A355792 A286093 A078827 * A328732 A130795 A367634

Adjacent sequences: A157803 A157804 A157805 * A157807 A157808 A157809

Keyword

nonn,look

Author

Ron R. King, Mar 07 2009

Extensions

Terms a(56) and beyond from Andrew Howroyd, Feb 03 2021

Status

approved