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A207507 Diameters of quadratic unitary Cayley graphs on the integers modulo n. 0
1, 1, 2, 2, 3, 1, 4, 2, 5, 1, 6, 2, 3, 3, 4, 2, 3, 1, 5, 3, 3, 1, 12, 2, 3, 2, 4, 2, 5, 1, 4, 3, 3, 3, 6, 2, 3, 2, 5, 2, 4, 1, 4, 3, 3, 1, 12, 2, 5, 2, 3, 2, 3, 3, 4, 3, 3, 1, 6, 2, 3, 3, 4, 3, 4, 1, 3, 3, 5, 1, 12 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,3

COMMENTS

Equivalently: the maximum number of terms required to express a nonzero residue modulo n, as a sum/difference of multiplicative units which are also quadratic residues.

LINKS

Table of n, a(n) for n=2..72.

N. de Beaudrap, On restricted unitary Cayley graphs and symplectic transformations modulo n, Electronic J. Combinatorics v17 (R69), 2010. See also arXiv:1002.0713.

CROSSREFS

Sequence in context: A035207 A324829 A294618 * A278537 A331803 A325184

Adjacent sequences:  A207504 A207505 A207506 * A207508 A207509 A207510

KEYWORD

nonn

AUTHOR

Niel de Beaudrap, Feb 18 2012

STATUS

approved

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Last modified May 17 23:07 EDT 2022. Contains 353779 sequences. (Running on oeis4.)