login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A047878 a(n)=least number of knight's moves from corner (0,0) to n-th diagonal of unbounded chessboard. 1
0, 3, 2, 1, 2, 3, 2, 3, 4, 3, 4, 5, 4, 5, 6, 5, 6, 7, 6, 7, 8, 7, 8, 9, 8, 9, 10, 9, 10, 11, 10, 11, 12, 11, 12, 13, 12, 13, 14, 13, 14, 15, 14, 15, 16, 15, 16, 17, 16, 17, 18, 17, 18, 19, 18, 19, 20, 19, 20, 21, 20, 21, 22, 21, 22, 23, 22, 23, 24, 23, 24, 25 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

a(n)=MIN{T(i,n-i): i=0,1,...,n}, array T as in A049604.

Apart from initial terms, same as A008611. - Anton Chupin, Oct 24 2009

LINKS

Table of n, a(n) for n=0..71.

Index entries for linear recurrences with constant coefficients, signature (1,0,1,-1).

FORMULA

a(3n)=n, a(3n+1)=n+1, a(3n+2)=n+2 for n >= 1.

a(n)=a(n-1)+a(n-3)-a(n-4) for n>5. G.f.: x*(2*x^4-2*x^3-x^2-x+3) / ((x-1)^2*(x^2+x+1)). - Colin Barker, May 04 2014

MATHEMATICA

LinearRecurrence[{1, 0, 1, -1}, {0, 3, 2, 1, 2, 3}, 80] (* Harvey P. Dale, Sep 01 2018 *)

PROG

(PARI) concat(0, Vec(x*(2*x^4-2*x^3-x^2-x+3)/((x-1)^2*(x^2+x+1)) + O(x^100))) \\ Colin Barker, May 04 2014

CROSSREFS

Sequence in context: A174543 A260450 A036583 * A324782 A256427 A120441

Adjacent sequences:  A047875 A047876 A047877 * A047879 A047880 A047881

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified February 16 15:17 EST 2020. Contains 331961 sequences. (Running on oeis4.)