Original entry on oeis.org
2, 14, 90, 612, 4608, 38760, 361440, 3688560, 41277600, 501379200, 6576837120, 92697696000, 1397414592000, 22498705152000, 382873642905600, 6908854669516800, 131496596027596800, 2633684945988096000
Offset: 1
Corrected and extended by Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 08 2003
Original entry on oeis.org
2, 8, 36, 180, 1080, 7560, 60480, 524160, 5241600, 56609280, 670602240, 8622028800, 118879488000, 1793381990400, 28158588057600, 474249904128000, 8447576417280000, 159659194286592000, 3162772610629632000, 66117689869271040000, 1445143792856924160000
Offset: 1
Corrected and extended by Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 08 2003
Original entry on oeis.org
2, 48, 25920, 522547200, 632073093120000, 68810005209415680000000, 922882872556916481982464000000000, 1930928443374224487368323197252403200000000000, 848408612299117898787190662782756632189835673600000000000000
Offset: 1
-
from functools import reduce
import operator
def a(n): return reduce(operator.mul, row(n), 1) # row(n) is given in A081957. - James Rayman, Jan 18 2021
Corrected and extended by Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 08 2003
A340727
a(n) is the smallest integer that can be written as a product of n distinct integers > 1 in at least two different ways.
Original entry on oeis.org
12, 48, 240, 1440, 8640, 60480, 604800, 5443200, 59875200, 718502400, 9340531200, 124540416000, 1743565824000, 29640619008000, 502146957312000, 8536498274304000, 162193467211776000, 3406062811447296000, 68121256228945920000, 1498667637036810240000
Offset: 2
a(2) = 12 since 12 = 2*6 = 3*4.
a(4) = 240 since 240 = 2*3*4*10 = 2*3*5*8.
-
from heapq import *
import math
def a(n):
prev, visited, v = 0, set(), list(range(2, n+2))
pq = [(math.factorial(n+1), v)]
while True:
prod, v = heappop(pq)
if tuple(v) in visited: continue
visited.add(tuple(v))
if prev != prod: prev = prod
else: return prod
for i in range(n):
if i == n-1 or v[i] + 1 < v[i+1]:
u = v[:]
u[i] += 1
heappush(pq, (prod // v[i] * u[i], u))
Showing 1-4 of 4 results.