A028666 -id:A028666 - cp's OEIS frontend

A144546 A bisection of A028666.

12, 11612160, 794088208701849600, 3575164027575627746190393606144000, 1055182047088717407398960909148529544369642384916480000, 20410164807073092317242309800149338693366138889849970301267088483593224192000000, 25872955740757748502626229629361173659982454517929458713719920139287952355803151825297413315474342543360000000

Offset: 0

N. J. A. Sloane, Dec 30 2008

nonn

Cf. A028666, A100221, A144547.

a[n_] := 4^(2*n+1) * Product[4^(2*n+1) - 4^k, {k, 0, 2*n}]; Array[a, 7, 0] (* Amiram Eldar, Jul 14 2025 *)

a(n) = 4^(2*n+1) * prod(k = 0, 2*n, 4^(2*n+1) - 4^k); \\ Amiram Eldar, Jul 14 2025

From Amiram Eldar, Jul 14 2025: (Start)
a(n) = A028666(2*n+1).
a(n) ~ c * 16^(2*n^2+3*n+1), where c = A100221. (End)

a(0) = 1 removed by Amiram Eldar, Jul 14 2025

A144547 A bisection of A028666.

Original entry on oeis.org

1, 2880, 758041804800, 13319336815141167562752000, 15354978274323252140217954794120612413440000, 1160183823755957350394353874696058298158177597536388268425216000000, 5744950321305805807513301436668994962443746225944514592041927656983526026246267317780480000000, 1864342934383580231084517260259192252139946430124547822192277172067265954040486594733297802503864086641393952539593932800000000

Offset: 0

N. J. A. Sloane, Dec 30 2008

nonn

Cf. A028666, A100221, A144546.

a[n_] := 16^n * Product[16^n - 4^k, {k, 0, 2*n-1}]; Array[a, 8, 0] (* Amiram Eldar, Jul 14 2025 *)

a(n) = 16^n * prod(k = 0, 2*n-1, 16^n - 4^k); \\ Amiram Eldar, Jul 14 2025

From Amiram Eldar, Jul 14 2025: (Start)
a(n) = A028666(2*n).
a(n) ~ c * 16^(2*n^2+n), where c = A100221. (End)

cp's OEIS Frontend

A144546 A bisection of A028666.

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