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 A262278 Number of binary strings of length 2n that are squares, but are not expressible as the concatenation of two or more squares. 1
 0, 2, 2, 6, 10, 24, 40, 92, 164, 408, 704, 1674, 3036, 7002, 12688, 29040, 53034, 119502, 219152, 487924, 900686, 1984664, 3683632, 8039958, 15012858, 32477788, 60988590, 130889590, 247193588, 526601802, 999873640, 2115798292 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Here by a "square" we mean a string of the form xx, where x is any string, like the English word "hotshots". LINKS EXAMPLE For n = 4 the 10 strings are (0001)^2, (0010)^2, (0100)^2, (0110)^2, (0111)^2, and their complements. PROG (PARI) MaxSquares(b, k)={if(b==0, k, my(r=-1); for(i=1, k, if(bitand(bitxor(b, b>>i), (1<>(2*i), k-i)))); if(r>=0, r+1, r))} a(n)={my(s=0); for(i=0, 2^(n-1)-1, if(MaxSquares(bitor(i<= 32 def MS(b, k):   if b == 0: return k   r = -1   for i in range(1, k+1):     if ((b^(b>>i)) & ((1<>(2*i), k-i))   return r+1 if r >= 0 else r @njit() # comment out for n >= 32 def a(n):   s = 0   for i in range(int(2**(n-1))):     s += MS((i<

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Last modified May 12 23:35 EDT 2021. Contains 343829 sequences. (Running on oeis4.)