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

 

Logo

The OEIS is looking to hire part-time people to help edit core sequences, upload scanned documents, process citations, fix broken links, etc. - Neil Sloane, njasloane@gmail.com

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A161701 (n^5 - 5*n^4 + 5*n^3 + 5*n^2 + 114*n + 120)/120. 20
1, 2, 3, 4, 6, 12, 28, 64, 135, 262, 473, 804, 1300, 2016, 3018, 4384, 6205, 8586, 11647, 15524, 20370, 26356, 33672, 42528, 53155, 65806, 80757, 98308, 118784, 142536, 169942, 201408, 237369, 278290, 324667, 377028, 435934, 501980, 575796, 658048 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

{a(k): 0 <= k < 6} = divisors of 12:

a(n) = A027750(A006218(11) + k + 1), 0 <= k < A000005(12).

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..10000

R. Zumkeller, Enumerations of Divisors

Index entries for linear recurrences with constant coefficients, signature (6,-15,20,-15,6,-1).

FORMULA

a(n) = C(n,0) + C(n,1) + C(n,4) + C(n,5).

G.f.: (1-4*x+6*x^2-4*x^3+2*x^4)/(1-x)^6. - Colin Barker, Aug 20 2012

EXAMPLE

Differences of divisors of 12 to compute the coefficients of their interpolating polynomial, see formula:

1 ... 2 ... 3 ... 4 ... 6 ... 12

.. 1 ... 1 ... 1 ... 2 ... 6

..... 0 ... 0 ... 1 ... 4

........ 0 ... 1 ... 3

........... 1 ... 2

.............. 1.

PROG

(MAGMA)[(n^5 - 5*n^4 + 5*n^3 + 5*n^2 + 114*n + 120)/120: n in [0..50]]; [From Vincenzo Librandi, Dec 27 2010]

(PARI) a(n)=(n^5-5*n^4+5*n^3+5*n^2+114*n+120)/120 \\ Charles R Greathouse IV, Sep 24 2015

CROSSREFS

A005408, A000124, A016813, A086514, A000125, A058331, A002522, A161702, A161703, A000127, A161704, A161706, A161707, A161708, A161710, A080856, A161711, A161712, A161713, A161715, A006261.

Sequence in context: A018369 A214570 A078495 * A038504 A275448 A018405

Adjacent sequences:  A161698 A161699 A161700 * A161702 A161703 A161704

KEYWORD

nonn,easy

AUTHOR

Reinhard Zumkeller, Jun 17 2009

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy .

Last modified May 30 06:51 EDT 2017. Contains 287302 sequences.