A261929 a(n) is the number of different pairs (p,q) mod n not of the form (x*y,x+y) mod n for any (x,y).

0, 1, 3, 8, 10, 18, 21, 36, 45, 55, 55, 96, 78, 112, 135, 160, 136, 216, 171, 280, 273, 286, 253, 408, 350, 403, 432, 560, 406, 630, 465, 656, 693, 697, 805, 1008, 666, 874, 975, 1180, 820, 1260, 903, 1408, 1485, 1288, 1081, 1728, 1323, 1675, 1683, 1976, 1378, 2025, 2035, 2352, 2109, 2059, 1711, 2880, 1830, 2356

Offset

1,3

Links

Table of n, a(n) for n=1..62.

Formula

a(n) = n^2 - A261928(n).

Example

a(2) = 1 because only the pair (1,1) mod 2 doesn't exist as result from any (x*y,x+y) mod 2.

Crossrefs

Cf. A261928 (number of pairs that have such a form).

Sequence in context: A341939 A244353 A143144 * A020488 A064435 A079541

Adjacent sequences: A261926 A261927 A261928 * A261930 A261931 A261932

Keyword

nonn

Author

Thomas Kerscher, Sep 06 2015

Status

approved