A388737 a(1) = 0, a(n) = abs(x) + abs(y), with x and y the next coordinates by using A028334 as a rectangular spiral.

0, 1, 2, 2, 1, 1, 2, 2, 3, 2, 1, 3, 2, 0, 3, 6, 5, 2, 4, 5, 2, 2, 5, 7, 5, 4, 6, 7, 5, 6, 8, 5, 4, 9, 10, 7, 4, 6, 9, 6, 5, 10, 11, 9, 8, 14, 20, 18, 17, 19, 22, 21, 16, 19, 22, 19, 18, 21, 23, 22, 17, 24, 26, 25, 23, 30, 33, 28, 27, 29, 32, 28, 25, 28, 30, 27

Offset

1,3

Links

Ruud H.G. van Tol, Table of n, a(n) for n = 1..30000

Example

a(24879) = 97; a(48507) = 93; a(464335) = 3.

Prog

(PARI) lista(nn) = my(x=0, y=0); vector(nn, n, if(n>1, my(t=(prime(n+1)-prime(n))/2*((-1)^(n%4>>1))); if(n%2, y-=t, x-=t)); abs(x)+abs(y))

Crossrefs

Cf. A028334, A002386.

Sequence in context: A337530 A269982 A329462 * A153864 A345128 A112399

Adjacent sequences: A388734 A388735 A388736 * A388738 A388739 A388740

Keyword

nonn

Author

Ruud H.G. van Tol, Sep 20 2025

Status

approved