A077138
a(0) = 0. If n is odd, a(n) = a(n-1) + n, otherwise a(n) = a(n-1) * n.
Original entry on oeis.org
0, 1, 2, 5, 20, 25, 150, 157, 1256, 1265, 12650, 12661, 151932, 151945, 2127230, 2127245, 34035920, 34035937, 612646866, 612646885, 12252937700, 12252937721, 269564629862, 269564629885, 6469551117240, 6469551117265, 168208329048890
Offset: 0
- William Boyles, Table of n, a(n) for n = 0..1000 [Terms 0 through 26 were computed by Amarnath Murthy; terms 27 through 1000 were computed by William Boyles, Nov 27 2016]
-
a = 0; Table[If[OddQ[n], a = n + a, a = n*a], {n, 0, 30}] (* T. D. Noe, Feb 26 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, Feb 13 2022 *)
-
a(n)=if(n<0,0,if(n%2,n+a(n-1),n*a(n-1)))
-
a=0
for n in range(1, 33):
print(a, end=', ')
if n&1:
a += n
else:
a *= n
A047904
a(n+1) = a(n) + n (if n is odd), a(n+1) = a(n) * n (if n is even).
Original entry on oeis.org
1, 2, 4, 7, 28, 33, 198, 205, 1640, 1649, 16490, 16501, 198012, 198025, 2772350, 2772365, 44357840, 44357857, 798441426, 798441445, 15968828900, 15968828921, 351314236262, 351314236285, 8431541670840, 8431541670865, 219220083442490
Offset: 1
Miklos SZABO (mike(AT)ludens.elte.hu)
-
a047904 n = a047904_list !! (n-1)
a047904_list = 1 : zipWith uncurry
(cycle [(+), (*)]) (zip a047904_list [1..])
-- Reinhard Zumkeller, Nov 13 2013, Mar 24 2013
-
Transpose[NestList[{#[[1]]+1,If[OddQ[#[[1]]],Total[#],Times@@#]}&,{1,1},30]][[2]] (* Harvey P. Dale, Sep 11 2012 *)
-
a=1
for n in range(1,33):
print(a, end=", ")
if n&1:
a += n
else:
a *= n
# Alex Ratushnyak, Feb 24 2013
A222559
a(0) = 0. If n is odd, a(n) = a(n-1) * n, otherwise a(n) = a(n-1) + n.
Original entry on oeis.org
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
-
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 *)
-
a=0
for n in range(1,33):
print(a, end=',')
if n&1:
a *= n
else:
a += n
A332657
Alternate adding and multiplying prime numbers: a(2n) = a(2n-1) * prime(2n+1) and a(2n-1) = a(2n) + prime(2n-2) for n >= 1.
Original entry on oeis.org
5, 25, 32, 352, 365, 6205, 6224, 143152, 143181, 4438611, 4438648, 181984568, 181984611, 8553276717, 8553276770, 504643329430, 504643329491, 33811103075897, 33811103075968, 2468210524545664, 2468210524545743, 204861473537296669, 204861473537296758
Offset: 1
a(1) = 2 + 3 = 5;
a(2) = 5 * 5 = 25;
a(3) = 25 + 7 = 32;
...
a(40) = 2714410084880275101596278688487175846.
-
from sympy import primerange
p = list(primerange(1, 200))
def a(n):
out = p[0] + p[1]
for i in range(1, n):
if i % 2:
out *= p[i + 1]
else:
out += p[i + 1]
return out
for n in range(1, 25):
print(a(n), end=", ")
A332659
Alternate multiplying and adding prime numbers: a(2n) = a(2n-1) + prime(2n+1) and a(2n-1) = a(2n) * prime(2n-2) for n >= 1.
Original entry on oeis.org
6, 11, 77, 88, 1144, 1161, 22059, 22082, 640378, 640409, 23695133, 23695174, 1018892482, 1018892529, 54001304037, 54001304096, 3294079549856, 3294079549923, 233879648044533, 233879648044606, 18476492195523874, 18476492195523957, 1644407805401632173
Offset: 1
a(1) = 2 * 3 = 6;
a(2) = 6 + 5 = 11;
a(3) = 11 * 7 = 77.
A332660
Alternate adding and multiplying Fibonacci numbers: a(0) = F(0) + F(1), for n >= 0, a(2n+1) = a(2n) * F(2n+2), a(2n+2) = a(2n+1) + F(2n+3).
Original entry on oeis.org
1, 1, 3, 9, 14, 112, 125, 2625, 2659, 146245, 146334, 21072096, 21072329, 7944268033, 7944268643, 7840993150641, 7840993152238, 20261126305382992, 20261126305387173, 137066519455944225345
Offset: 0
a(0) = 0 + 1 = 1;
a(1) = 1 * 1 = 1;
a(2) = 1 + 2 = 3;
a(3) = 3 * 3 = 9;
a(4) = 9 + 5 = 14.
-
a[0] = 1; a[n_] := a[n] = If[OddQ[n], a[n-1] * Fibonacci[n+1], a[n-1] + Fibonacci[n+1]]; Array[a, 20, 0] (* Amiram Eldar, Mar 28 2020 *)
-
from sympy import fibonacci
f = [fibonacci(n) for n in range(100)]
def a(n):
out = f[0] + f[1]
for i in range(1, n):
if i%2:
out *= f[i+1]
else:
out += f[i+1]
return out
A333591
Alternate multiplying and adding Fibonacci numbers: a(0) = F(0) * F(1), for n >= 0, a(2n+1) = a(2n) + F(2n+2), a(2n+2) = a(2n+1) * F(2n+3).
Original entry on oeis.org
0, 1, 2, 5, 25, 33, 429, 450, 15300, 15355, 1366595, 1366739, 318450187, 318450564, 194254844040, 194254845027, 310224987508119, 310224987510703, 1297050672782249243, 1297050672782256008, 14197516664274574263568, 14197516664274574281279
Offset: 0
a(0) = 0 * 1 = 0;
a(1) = 0 + 1 = 1;
a(2) = 1 * 2 = 2;
a(3) = 2 + 3 = 5;
a(4) = 5 * 5 = 25.
-
a[0] = 0; a[n_] := a[n] = If[EvenQ[n], a[n-1] * Fibonacci[n+1], a[n-1] + Fibonacci[n+1]]; Array[a, 22, 0] (* Amiram Eldar, Mar 28 2020 *)
-
from sympy import fibonacci
f = [fibonacci(n) for n in range(200)]
def a(n):
out = f[0] * f[1]
for i in range(1, n+1):
if i%2:
out += f[i+1]
else:
out *= f[i+1]
return out
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