A284520 a(1) = 1, a(2) = a(3) = a(4) = 2; a(n) = a(a(n-1)-1) + a(n-a(n-3)-1) for n > 4.

1, 2, 2, 2, 3, 4, 4, 4, 4, 5, 6, 7, 8, 8, 8, 8, 8, 8, 9, 10, 11, 12, 13, 14, 15, 15, 15, 15, 16, 16, 16, 16, 16, 16, 16, 17, 18, 19, 19, 19, 19, 20, 22, 25, 28, 28, 26, 24, 23, 25, 29, 30, 31, 30, 30, 30, 31, 31, 31, 31, 32, 32, 32, 32, 32, 32, 32, 32, 33, 34, 35, 35, 35

Offset

1,2

Links

Altug Alkan, Table of n, a(n) for n = 1..20000

Altug Alkan, Scatterplot of A284520

Example

a(5) = 3 because a(5) = a(a(4)-1) + a(5-a(2)-1) = a(1) + a(2) = 3.

Prog

(PARI) a=vector(1000); a[1]=1; a[2]=a[3]=a[4]=2; for(n=5, #a, a[n]=a[a[n-1]-1]+ a[n-a[n-3]-1]); a

Crossrefs

Cf. A004001, A005185, A005229, A055748, A070867, A226222, A284511.

Sequence in context: A359536 A194814 A055748 * A369057 A342248 A357604

Adjacent sequences: A284517 A284518 A284519 * A284521 A284522 A284523

Keyword

nonn,look

Author

Altug Alkan, Mar 28 2017

Status

approved