cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A230951 Boustrophedon transform of Thue-Morse sequence A010059.

Original entry on oeis.org

1, 1, 1, 3, 9, 27, 108, 475, 2421, 13859, 88254, 617957, 4720980, 39070669, 348225424, 3325303894, 33871280413, 366573108019, 4200618576106, 50809739256049, 646929695900154, 8648812936664311, 121132117170628444, 1773647319453218254, 27099334868109293640
Offset: 0

Views

Author

Reinhard Zumkeller, Nov 03 2013

Keywords

Crossrefs

Programs

  • Haskell
    a230951 n = sum $ zipWith (*) (a109449_row n) $ map fromIntegral a010059_list
    
  • Python
    from itertools import count, islice, accumulate
    def A230951_gen(): # generator of terms
        blist = tuple()
        for i in count(0):
            yield (blist := tuple(accumulate(reversed(blist), initial=i.bit_count()&1^1)))[-1]
    A230951_list = list(islice(A230951_gen(),30)) # Chai Wah Wu, Apr 17 2023

Formula

a(n) = Sum_{k=0..n} A109449(n,k)*A010059(k).