A327879 Number of primitive (period n) periodic palindromes with integer entries that cover an initial interval of positive integers.

1, 1, 1, 2, 6, 12, 40, 74, 300, 538, 2598, 4682, 25938, 47292, 296488, 545820, 3816240, 7087260, 54666830, 102247562, 862437450, 1622632496, 14857095400, 28091567594, 277474931700, 526858348368, 5584100612118, 10641342969902, 120462266677578

Offset

0,4

Links

Andrew Howroyd, Table of n, a(n) for n = 0..200

Formula

Moebius transform of A327868.

Example

The a(4) = 6 primitive periodic palindromes are:
  1122, 1112, 1222,
  1213, 1232, 1323.

Prog

(PARI) a(n)={if(n<1, n==0, sumdiv(n, d, moebius(n/d)*sum(k=0, n, k!*(stirling((d+1)\2, k, 2)+stirling(d\2+1, k, 2))))/2)}

Crossrefs

Row sums of A327878.

Cf. A327868, A327874.

Sequence in context: A225957 A123045 A280171 * A094261 A080497 A127724

Adjacent sequences: A327876 A327877 A327878 * A327880 A327881 A327882

Keyword

nonn

Author

Andrew Howroyd, Sep 28 2019

Status

approved