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

 

Logo

Annual Appeal: Please make a donation (tax deductible in USA) to keep the OEIS running. Over 5000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A128198 Array read by antidiagonals. A scheme of arrangements: ArrScheme(k,n) = VarScheme(k,n-1) + k^n; ArrScheme(k,0) = 1. VarScheme(k,n) = (n*k+1)*(VarScheme(k,n-1) + k^n); VarScheme(k,0) = 1. 0
1, 1, 1, 1, 2, 1, 1, 3, 5, 1, 1, 4, 13, 16, 1, 1, 5, 25, 73, 65, 1, 1, 6, 41, 202, 527, 326, 1, 1, 7, 61, 433, 2101, 4775, 1957, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,5

COMMENTS

The second row (k=1) is sequence A000522 counting the arrangements of a set with n elements and the third row (k=2) is the sequence A128196. Cf. the scheme of variations A128195.

LINKS

Table of n, a(n) for n=0..35.

P. Luschny, Variants of Variations.

EXAMPLE

Array begins:

[k=0] 1, 1, 1, 1, 1, 1, 1, 1

[k=1] 1, 2, 5, 16, 65, 326, 1957, 13700

[k=2] 1, 3, 13, 73, 527, 4775, 52589, 683785

[k=3] 1, 4, 25, 202, 2101, 27556, 441625, 8393062

[k=4] 1, 5, 41, 433, 5885, 101069, 2126545, 53180009

[k=5] 1, 6, 61, 796, 13361, 283706, 7391981, 229229536

[k=6] 1, 7, 85, 1321, 26395, 667651, 20743837, 767801905

[k=7] 1, 8, 113, 2038, 47237, 1386680, 50038129, 2152463090

MAPLE

VarScheme := (k, n) -> `if`(n=0, 1, (n*k+1)*(VarScheme(k, n-1)+k^n)); ArrScheme := (k, n) -> `if`(n=0, 1, VarScheme(k, n-1)+k^n);

CROSSREFS

Cf. A000522, A128195, A128196, A126062.

Sequence in context: A241578 A112338 A111672 * A123349 A123352 A114163

Adjacent sequences:  A128195 A128196 A128197 * A128199 A128200 A128201

KEYWORD

easy,nonn,tabl

AUTHOR

Peter Luschny, Mar 02 2007

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 December 8 10:49 EST 2016. Contains 278939 sequences.