The OEIS is supported by the many generous donors to the OEIS Foundation.

 Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”). Other ways to Give
 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A126375 Number of base 21 n-digit numbers with adjacent digits differing by one or less. 4

%I

%S 1,21,61,179,527,1555,4595,13593,40245,119235,353459,1048285,3110249,

%T 9231305,27407185,81392387,241773327,718335747,2134675683,6344739309,

%U 18861068265,56076828573,166747755621,495896780609,1474935978225

%N Number of base 21 n-digit numbers with adjacent digits differing by one or less.

%C [Empirical] a(base,n)=a(base-1,n)+3^(n-1) for base>=n; a(base,n)=a(base-1,n)+3^(n-1)-2 when base=n-1.

%F G.f.: (1+10*x-126*x^2+366*x^3-166*x^4-700*x^5+679*x^6+426*x^7-466*x^8-104*x^9+73*x^10+6*x^11) / ((1-x)*(1-10*x+34*x^2-32*x^3-54*x^4+100*x^5+23*x^6-76*x^7-10*x^8+12*x^9+x^10)) (conjectured). - _Colin Barker_, Jul 18 2017

%o (S/R) stvar \$[N]:(0..M-1) init \$[]:=0 asgn \$[]->{*} kill +[i in 0..N-2]((\$[i]`-\$[i+1]`>1)+(\$[i+1]`-\$[i]`>1))

%K nonn,base

%O 0,2

%A _R. H. Hardin_, Dec 26 2006

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

Last modified December 4 23:46 EST 2022. Contains 358572 sequences. (Running on oeis4.)