A003833 Sectors around outside of dartboard.

20, 1, 18, 4, 13, 6, 10, 15, 2, 17, 3, 19, 7, 16, 8, 11, 14, 9, 12, 5, 20, 1, 18, 4, 13, 6, 10, 15, 2, 17, 3, 19, 7, 16, 8, 11, 14, 9, 12, 5, 20, 1, 18, 4, 13, 6, 10, 15, 2, 17, 3, 19, 7, 16, 8, 11, 14, 9, 12, 5, 20, 1, 18, 4, 13, 6, 10, 15, 2, 17, 3, 19, 7, 16, 8, 11, 14, 9

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Comments

Known as the standard, London or clock dartboard.

Periodic with period 20. - Paolo Xausa, Jul 14 2025

References

• Marilyn vos Savant, "Ask Marilyn," in 'Parade, The Sunday Newspaper Magazine,' page 12, Sunday, Jan 12, 2003.

Links

• Paolo Xausa, Table of n, a(n) for n = 1..10000
• K. S. Brown, The Dartboard Sequence
• American Darts Organization, Home page
• World Darts Federation, WDF Playing and Tournament Rules
• Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1).

Crossrefs

Cf. A008575, A104159.

Programs

Mathematica

PadRight[{}, 100, {20, 1, 18, 4, 13, 6, 10, 15, 2, 17, 3, 19, 7, 16, 8, 11, 14, 9, 12, 5}] (* Paolo Xausa, Jul 14 2025 *)