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 A320434 Number of length-n quasiperiodic binary strings. 2
 0, 2, 2, 4, 4, 10, 10, 26, 22, 56, 68, 118, 126, 284, 274, 542, 604, 1144, 1196, 2284, 2340, 4600, 4876, 9010, 9280, 18286, 18476, 35546, 36886, 70320, 72092, 140578, 141736, 276812, 282694 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS A length-n string x is quasiperiodic if some proper prefix t of x can completely cover x by shifting, allowing overlaps. For example, 01010010 is quasiperiodic because it can be covered by shifted occurrences of 010. LINKS A. Apostolico, M. Farach, and C. S. Iliopoulos, Optimal superprimitivity testing for strings, Info. Proc. Letters 39 (1991), 17-20. Rémy Sigrist, C program for A320434 FORMULA a(n) = 2^n - A216215(n). - Rémy Sigrist, Jan 08 2019 EXAMPLE For n = 5 the quasiperiodic strings are 00000, 01010, and their complements. PROG (C) See Links section. CROSSREFS Cf. A216215. Sequence in context: A286088 A005293 A287488 * A329394 A057784 A209284 Adjacent sequences:  A320431 A320432 A320433 * A320435 A320436 A320437 KEYWORD nonn,more AUTHOR Jeffrey Shallit, Jan 08 2019 EXTENSIONS a(18)-a(30) from Rémy Sigrist, Jan 08 2019 a(31)-a(35) from Rémy Sigrist, Jan 09 2019 STATUS approved

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Last modified February 25 12:01 EST 2020. Contains 332233 sequences. (Running on oeis4.)