OFFSET
0,4
COMMENTS
Circularity means the last part is followed by the first.
LINKS
Andrew Howroyd, Table of n, a(n) for n = 0..200
FORMULA
a(n > 1) = A318748(n) - 1.
EXAMPLE
The a(1) = 1 through a(6) = 23 compositions:
(1) (11) (12) (13) (14) (15)
(21) (31) (23) (51)
(111) (112) (32) (114)
(121) (41) (123)
(211) (113) (132)
(1111) (131) (141)
(311) (213)
(1112) (231)
(1121) (312)
(1211) (321)
(2111) (411)
(11111) (1113)
(1131)
(1212)
(1311)
(2121)
(3111)
(11112)
(11121)
(11211)
(12111)
(21111)
(111111)
MATHEMATICA
Table[Length[Select[Join@@Permutations/@IntegerPartitions[n], And@@CoprimeQ@@@Partition[#, 2, 1, 1]&]], {n, 10}]
PROG
(PARI)
b(n, q, pred)={my(M=matrix(n, n)); for(k=1, n, M[k, k]=pred(q, k); for(i=1, k-1, M[i, k]=sum(j=1, k-i, if(pred(j, i), M[j, k-i], 0)))); M[q, ]}
seq(n)={concat([1], sum(k=1, n, b(n, k, (i, j)->gcd(i, j)==1)))} \\ Andrew Howroyd, Nov 01 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Oct 26 2019
STATUS
approved