A283451 a(n) = Sum_{k=1..n} (-1)^k * A005185(k).

-1, 0, -2, 1, -2, 2, -3, 2, -4, 2, -4, 4, -4, 4, -6, 3, -7, 4, -7, 5, -7, 5, -7, 9, -5, 9, -7, 9, -7, 9, -11, 6, -11, 9, -12, 7, -13, 9, -12, 10, -13, 10, -14, 10, -14, 10, -14, 18, -6, 19, -11, 17, -9, 21, -9, 19, -13, 17, -15, 17, -15, 17, -23, 10, -21, 17, -18, 15, -24, 16, -21

Offset: 1

Author

Altug Alkan, Mar 07 2017

Keywords

• sign
• look

Examples

			a(7) = -3 because -1 + 1 - 2 + 3 - 3 + 4 - 5 = -3.
		

Links

• Altug Alkan, Table of n, a(n) for n = 1..10000
• Altug Alkan, Alternative Scatterplot of A283451

Crossrefs

Cf. A005185, A076268.

Programs

PARI

a=vector(1000); a[1]=a[2]=1; for(n=3, #a, a[n]=a[n-a[n-1]]+a[n-a[n-2]]); va = vector(#a, n, sum(k=1, n, (-1)^(k)*a[k]))