A005510 a(n) = 1 + a(floor(n/2))*a(ceiling(n/2)) for n > 1, a(1) = 3. (Formerly M2842)

3, 10, 31, 101, 311, 962, 3132, 10202, 31412, 96722, 299183, 925445, 3012985, 9809425, 31952665, 104080805, 320465225, 986713745, 3038231465, 9355145285, 28937578127, 89510467490, 276877411436, 856448448026, 2788351903326, 9078078610226, 29555650383626

Offset

1,1

Comments

All terms are congruent to 3 mod 7.

References

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Table of n, a(n) for n=1..27.

Maple

a:= proc(n) option remember; `if`(n=1, 3,
      1+(t->a(t)*a(n-t))(iquo(n, 2)))
    end:
seq(a(n), n=1..30);  # Alois P. Heinz, Jul 04 2019

Crossrefs

Cf. A005468, A005469.

Sequence in context: A214839 A114487 A017934 * A005725 A302287 A079522

Adjacent sequences: A005507 A005508 A005509 * A005511 A005512 A005513

Keyword

nonn,easy

Author

Colin Mallows

Status

approved