A287794 Nine steps forward, eight steps back.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 8, 7, 6, 5, 4, 3, 2, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 9, 8, 7, 6, 5, 4, 3, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 10, 9, 8, 7, 6, 5, 4, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 11, 10, 9, 8, 7, 6, 5, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 12, 11, 10

Offset

0,3

Links

Table of n, a(n) for n=0..80.

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

Formula

a(n) = Sum_{i=1..n} (-1)^floor((2*i-2)/17).

a(n) = a(n-1) + a(n-17) - a(n-18) for n > 17.

Maple

a:=n->add((-1)^floor((2*i-2)/17), i=1..n): seq(a(n), n=0..200);

Mathematica

Table[Sum[(-1)^Floor[(2 i - 2)/17], {i, n}], {n, 0, 100}]

Crossrefs

Cf. A008611 (one step back, two steps forward).

Cf. A058207 (three steps forward, two steps back).

Cf. A260644 (four steps forward, three steps back).

Cf. A271800 (five steps forward, four steps back).

Cf. A271859 (six steps forward, five steps back).

Cf. A287655 (seven steps forward, six steps back).

Cf. A287793 (eight steps forward, seven steps back).

Sequence in context: A158289 A213652 A262734 * A179987 A073796 A017894

Adjacent sequences: A287791 A287792 A287793 * A287795 A287796 A287797

Keyword

nonn,easy

Author

Wesley Ivan Hurt, May 31 2017

Status

approved