A103487 a(0)=7; a(1)=11; a(2)=13; a(3)=17; a(n) = |a(n-2)+a(n-3)-a(n-4)|.

7, 11, 13, 17, 17, 19, 21, 19, 23, 21, 21, 25, 19, 25, 23, 19, 29, 17, 25, 27, 13, 35, 15, 21, 37, 1, 43, 17, 7, 59, 19, 49, 71, 9, 101, 31, 39, 123, 31, 131, 115, 39, 215, 23, 139, 199, 53, 315, 113, 169, 375, 33, 431, 239, 89, 637, 103, 487, 651, 47, 1035, 211, 431, 1199

Offset

0,1

Comments

Has an interesting and irregular behavior.

Links

Table of n, a(n) for n=0..63.

Mathematica

a[0] = 7; a[1] = 11; a[2] = 13; a[3] = 17; a[n_Integer?Positive] := a[n] = Abs[ a[n - 2] + a[n - 3] - a[n - 4]]; Table[ a[n], {n, 0, 65}]

Crossrefs

Sequence in context: A172120 A112090 A373673 * A175811 A373140 A112588

Adjacent sequences: A103484 A103485 A103486 * A103488 A103489 A103490

Keyword

nonn

Author

Roger L. Bagula, Mar 21 2005

Extensions

More terms from Robert G. Wilson v, Apr 13 2005

Status

approved