login
A327879
Number of primitive (period n) periodic palindromes with integer entries that cover an initial interval of positive integers.
3
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
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.
Sequence in context: A225957 A123045 A280171 * A094261 A080497 A127724
KEYWORD
nonn
AUTHOR
Andrew Howroyd, Sep 28 2019
STATUS
approved