A245367 Compositions of n into parts 3, 5 and 7.

1, 0, 0, 1, 0, 1, 1, 1, 2, 1, 3, 3, 3, 6, 5, 8, 10, 11, 17, 18, 25, 32, 37, 52, 61, 79, 102, 123, 163, 200, 254, 326, 402, 519, 649, 819, 1045, 1305, 1664, 2096, 2643, 3358, 4220, 5352, 6759, 8527, 10806, 13622, 17237, 21785, 27501, 34802, 43934, 55544, 70209, 88672, 112131, 141644, 179018, 226274, 285860, 361358

Offset: 0

Author

David Neil McGrath, Aug 20 2014

Keywords

• nonn
• easy

Examples

			a(16) = 10: the compositions are the permutations of [5533] (there are 4!/2!2!=6 of them) and the permutations of [7333] (there are 4!/3!=4).
		

Links

• Index entries for linear recurrences with constant coefficients, signature (0,0,1,0,1,0,1).

Crossrefs

Cf. A000073, A013979, A017818, A060945, A079956, A079957, A079971, A079973, A120400, A121833.

Programs

Mathematica

LinearRecurrence[{0,0,1,0,1,0,1},{1,0,0,1,0,1,1},70] (* Harvey P. Dale, Jan 27 2017 *)

PARI

Vec(1/(1-x^3-x^5-x^7) +O(x^66)) \\ Joerg Arndt, Aug 20 2014

Formula

G.f: 1/(1-x^3-x^5-x^7).

a(n) = a(n-3) + a(n-5) + a(n-7).