login
This site is supported by donations to The OEIS Foundation.
Logo

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A133180 sum[k^6]/sum[k^2], {k, 1, A047380(n)}]. 6
1, 13, 163, 373, 2191, 3433, 7411, 10363, 24583, 31591, 49981, 61723, 109513, 130351, 180793, 210901, 324013, 370273, 477463, 539041, 759811, 846613, 1042303, 1151983, 1533331, 1679323, 2002321, 2180263, 2785693, 3013051, 3509221 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

A000540(n) is divisible by A000330(n) if and only n is congruent to {1,2,4,5} mod 7 (see A047380) A133180 is union of A134158 and A134159 and A134160 and A134161

LINKS

Table of n, a(n) for n=0..30.

FORMULA

a(n) = sum[k^6]/sum[k^2], {k, 1, A047380(n)}]

MATHEMATICA

a = {}; Do[j = Sum[k^6, {k, 1, n}]/Sum[k^2, {k, 1, n}]; If[IntegerQ[j], AppendTo[a, j]], {n, 1, 100}] ; a (*Artur Jasinski*)

CROSSREFS

Cf. A000330, A000540, A119617, A134153, A134154, A134158, A134159, A134160, A134161.

Sequence in context: A118673 A216300 A212785 * A090134 A087400 A012828

Adjacent sequences:  A133177 A133178 A133179 * A133181 A133182 A133183

KEYWORD

nonn

AUTHOR

Artur Jasinski, Oct 10 2007

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified May 23 17:33 EDT 2013. Contains 225610 sequences.