This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A297702 Number of length-n binary strings where every prefix is either a palindrome, or the concatenation of two palindromes. 0
 1, 2, 4, 8, 16, 32, 52, 88, 134, 184, 254, 342, 422, 530, 658, 770, 922, 1090, 1248, 1438, 1640, 1834, 2090, 2334, 2570, 2842, 3158, 3432, 3762, 4104, 4438, 4810, 5210, 5568, 6022, 6420, 6858, 7344, 7852, 8292, 8816, 9352, 9894, 10448, 11056, 11584, 12274, 12880, 13498, 14168, 14886, 15530, 16298, 17002, 17754 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS EXAMPLE For n = 6 the 12 missing strings are 001011,001101,010011,010110,011001,011010 and their bitwise complements. MAPLE g:= proc(L) local k;   if L = ListTools:-Reverse(L) then return true fi;   for k from 1 to nops(L)-1 do     if L[1..k]=ListTools:-Reverse(L[1..k]) and L[k+1..-1] = ListTools:-Reverse(L[k+1..-1]) then return true fi;   od:   false end proc: A[0]:= 1: S:= [[]]: for n from 1 to 55 do   S:= select(g, map(t -> ([op(t), 0], [op(t), 1]), S));   A[n]:= nops(S); od: seq(A[i], i=0..55); # Robert Israel, Jan 03 2018 CROSSREFS Sequence in context: A222193 A217833 A226930 * A306314 A007055 A175951 Adjacent sequences:  A297699 A297700 A297701 * A297703 A297704 A297705 KEYWORD nonn AUTHOR Jeffrey Shallit, Jan 03 2018 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.

Last modified June 25 23:52 EDT 2019. Contains 324367 sequences. (Running on oeis4.)