A087417 Sum of the cubes of A058182.

-1, 0, 0, 1, 2, 10, 135, 19818, 395466722, 156401766357161409, 24461512581491800525933058683030176

Offset

0,5

Comments

The sequence A058182=b(n) has the property: b(1)^3+b(2)^3+b(3)^3+...b(n)^3=b(n)*b(n+1)

Links

Table of n, a(n) for n=0..10.

Formula

a(n+1) = a(n) + A058182(n)^3, a(-n) = a(n) for all n in Z.

Example

A058182 begins 1,1,2,5,27,734,538783...=b(n)
1^3+1^3=2=a(2)=1*2=b(2)*b(3).
1^3+1^3+2^3=10=a(3)=2*5=b(3)*b(4).
1^3+1^3+2^3+5^3=135=a(4)=5*27=b(4)*b(5).
1^3+1^3+2^3+5^3+27^3=19818=a(5)=b(5)*b(6).

Prog

(PARI) {a(n) = local(a0, a1, a2); if( n<0, a(-n), if( n<3, -(n==0), a0 = a1 = 1; for(i=4, n, a2 = a1^2 + a0; a0 = a1; a1 = a2); a1*a0))}; /* Michael Somos, May 22 2005 */

Crossrefs

Cf. A058182.

Sequence in context: A134051 A075199 A134981 * A270589 A171214 A213955

Adjacent sequences: A087414 A087415 A087416 * A087418 A087419 A087420

Keyword

sign

Author

Miklos Kristof, Oct 22 2003

Status

approved