A090962 Least multiple of n such that the n-th partial sum is an n-th power with the condition that a(n+1) exists.

1, 8, 207, 40, 7520, 38880, 2050496, 14680064, 983222784, 9000000000, 733008370688, 8173092077568, 784798672805888, 10318292052303872, 1141809497781288960, 1025031833202524160, 2183733606400887160832

Offset

1,2

Links

Table of n, a(n) for n=1..17.

Example

a(2) = 8, yielding the 2nd partial sum 1 + 8 = 9 = 3^2.
a(3) cannot be j^3 - 9 for j = 3, 4, or 5, because there would be no number k such that j^3 + 4k = is a 4th power; thus, a(3) = 207, yielding the 3rd partial sum 9 + 207 = 216 = 6^3 (and a(4) = 4^4 - 6^3 = 40).

Crossrefs

Cf. A090963.

Sequence in context: A204247 A063856 A367540 * A359281 A359452 A330287

Adjacent sequences: A090959 A090960 A090961 * A090963 A090964 A090965

Keyword

nonn

Author

Amarnath Murthy, Jan 02 2004

Extensions

More terms from David Wasserman, Feb 23 2006

Status

approved