A268537 Number of Skolem sequences of order n, as n runs through the positive integers congruent to 0 and 1 mod 4.

1, 6, 10, 504, 2656, 455936, 3040560, 1400156768, 12248982496, 11435578798976, 123564928167168, 204776117691241344, 2634563519776965376, 7064747252076429464064, 105435171495207196553472

Offset

1,2

Links

Table of n, a(n) for n=1..15.

Ali Assarpour, Amotz Bar-Noy, and Ou Liuo, Counting the Number of Langford Skolem Pairings, arXiv:1507.00315 [cs.DM], 2015.

James Bubear, Joanne Hall, Kevin Hendrey, and Tim Wilson, Skolem Circles, arXiv:1602.08879 [math.CO], 2016.

Formula

a(n) = A004075(2*n - (n mod 2)) = A004075(A042948(n)).

Crossrefs

This is A004075 without the zeros.

Cf. A042948.

Sequence in context: A124902 A153022 A262081 * A115677 A284738 A100129

Adjacent sequences: A268534 A268535 A268536 * A268538 A268539 A268540

Keyword

nonn

Author

N. J. A. Sloane, Feb 22 2016

Extensions

a(14)-a(15) from A004075 added by Max Alekseyev, Sep 26 2023

Status

approved