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

 

Logo

Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing.
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A094626 Expansion of x*(1+x)/((1-x)*(1-10*x^2)). 19
0, 1, 2, 12, 22, 122, 222, 1222, 2222, 12222, 22222, 122222, 222222, 1222222, 2222222, 12222222, 22222222, 122222222, 222222222, 1222222222, 2222222222, 12222222222, 22222222222, 122222222222, 222222222222, 1222222222222, 2222222222222, 12222222222222 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Previous name: Sequence whose n-th term digits sum to n.

a(n) is the smallest integer with digits from {0,1,2} having digit sum n. Namely the base-10 reading of the ternary string of A062318. - Jason Kimberley, Nov 01 2011

a(n) is the Moore lower bound on the order of an (11,n)-cage. - Jason Kimberley, Oct 18 2011

LINKS

Colin Barker, Table of n, a(n) for n = 0..1000

G. Royle, Cages of higher valency

Index entries for linear recurrences with constant coefficients, signature (1,10,-10).

FORMULA

G.f.: x*(1+x)/((1-x)*(1-10*x^2)).

a(n) = 10^(n/2)*(11*sqrt(10)/180 + 1/9 - (11*sqrt(10)/180 - 1/9)*(-1)^n) - 2/9.

From Colin Barker, Mar 17 2017: (Start)

a(n) = 2*(10^(n/2) - 1)/9 for n even.

a(n) = (11*10^((n-1)/2) - 2)/9 for n odd.

(End)

PROG

(PARI) concat(0, Vec(x*(1+x)/((1-x)*(1-10*x^2)) + O(x^30))) \\ Colin Barker, Mar 17 2017

CROSSREFS

Cf. A094623, A094624.

Moore lower bound on the order of a (k,g) cage: A198300 (square); rows: A000027 (k=2), A027383 (k=3), A062318 (k=4), A061547 (k=5), A198306 (k=6), A198307 (k=7), A198308 (k=8), A198309 (k=9), A198310 (k=10), this sequence (k=11); columns: A020725 (g=3), A005843 (g=4), A002522 (g=5), A051890 (g=6), A188377 (g=7). - Jason Kimberley, Nov 01 2011

Sequence in context: A111095 A073211 A233137 * A093378 A012664 A012545

Adjacent sequences:  A094623 A094624 A094625 * A094627 A094628 A094629

KEYWORD

easy,nonn,base

AUTHOR

Paul Barry, May 15 2004

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
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 14 09:41 EST 2019. Contains 329979 sequences. (Running on oeis4.)