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A285042
Number of primitive (period n) periodic palindromic structures of length n using an infinite alphabet.
4
1, 1, 1, 1, 3, 4, 10, 14, 36, 50, 138, 202, 562, 876, 2589, 4134, 12828, 21146, 69115, 115974, 398619, 678554, 2450202, 4213596, 15939338, 27644432, 109304036, 190899270, 787013630, 1382958544, 5931819804, 10480142146, 46673246440, 82864869600, 382473261356
OFFSET
0,5
COMMENTS
See A285037 for additional information. Permuting the symbols will not change the structure.
LINKS
FORMULA
a(n) = Sum_{d | n} mu(n/d) * A285013(d) for n > 0.
PROG
(PARI) \\ Requires T from A285037.
seq(n)={my(A=T(n)); concat([1], vector(n, i, vecsum(A[i, ])))} \\ Andrew Howroyd, Oct 02 2019
CROSSREFS
Row sums of A285037.
Cf. A285013.
Sequence in context: A056515 A056516 A056517 * A319719 A347568 A048155
KEYWORD
nonn
AUTHOR
Andrew Howroyd, Apr 08 2017
EXTENSIONS
a(0)=1 prepended and terms a(28) and beyond from Andrew Howroyd, Oct 02 2019
STATUS
approved