|
|
A005477
|
|
a(n) = 2^(n-1)*(2^n - 1)*Product_{j=1..n-1} (2^j + 1).
|
|
1
|
|
|
0, 1, 18, 420, 16200, 1138320, 152681760, 40012315200, 20727639504000, 21349793828563200, 43852643645542617600, 179883715700853141120000, 1474687052822610564537600000, 24170122236238340825650936320000
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,3
|
|
LINKS
|
|
|
FORMULA
|
a(n) = 2^(n-2)*(2^n - 1)*QPochhammer(n, -1, 2). - G. C. Greubel, Nov 25 2022
|
|
MAPLE
|
f := i->2^(i-1)*(2^i-1)*product( '2^j+1', 'j'=1..i-1);
|
|
MATHEMATICA
|
Table[2^(n-1) (2^n-1)Product[2^j+1, {j, n-1}], {n, 0, 20}] (* Harvey P. Dale, Feb 02 2022 *)
Table[2^(n-2)*(2^n-1)*QPochhammer[-1, 2, n], {n, 0, 30}] (* G. C. Greubel, Nov 25 2022 *)
|
|
PROG
|
(Magma) [n le 1 select n else 2^(n-1)*(2^n -1)*(&*[2^j+1: j in [1..n-1]]): n in [0..25]]; // G. C. Greubel, Nov 25 2022
(SageMath)
def A005477(n): return 2^(n-2)*(2^n-1)*product(2^j+1 for j in range(n))
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|