A222559 a(0) = 0. If n is odd, a(n) = a(n-1) * n, otherwise a(n) = a(n-1) + n.

0, 0, 2, 6, 10, 50, 56, 392, 400, 3600, 3610, 39710, 39722, 516386, 516400, 7746000, 7746016, 131682272, 131682290, 2501963510, 2501963530, 52541234130, 52541234152, 1208448385496, 1208448385520, 30211209638000, 30211209638026, 815702660226702, 815702660226730

Offset

0,3

Links

Harvey P. Dale, Table of n, a(n) for n = 0..808

Mathematica

last = 0; Table[If[OddQ[n], last = n * last, last = n + last], {n, 0, 40}] (* T. D. Noe, Mar 01 2013 *)
nxt[{n_, a_}]:={n+1, If[EvenQ[n], a(n+1), a+n+1]}; NestList[nxt, {0, 0}, 30][[All, 2]] (* Harvey P. Dale, May 14 2019 *)

Prog

(Python)
a=0
for n in range(1, 33):
    print(a, end=', ')
    if n&1:
        a *= n
    else:
        a += n

Crossrefs

Cf. A077138, A047904, A047905.

Sequence in context: A298760 A153803 A083524 * A095107 A115113 A163788

Adjacent sequences: A222556 A222557 A222558 * A222560 A222561 A222562

Keyword

nonn,easy

Author

Alex Ratushnyak, Feb 24 2013

Status

approved