A100777 Square-factorial numbers: a(1) = 1, a(n+1) = a(n) * largest square divisor of (n+1).

1, 1, 1, 4, 4, 4, 4, 16, 144, 144, 144, 576, 576, 576, 576, 9216, 9216, 82944, 82944, 331776, 331776, 331776, 331776, 1327104, 33177600, 33177600, 298598400, 1194393600, 1194393600, 1194393600, 1194393600, 19110297600, 19110297600, 19110297600, 19110297600

Offset

1,4

Comments

Complementary to A048803 which can be defined as squarefree factorials.

Partial products of A008833. - Ray Chandler, Nov 29 2004

Links

Amiram Eldar, Table of n, a(n) for n = 1..2135

Mathematica

f[p_, e_] := p^(2*Floor[e/2]); s[n_] := Times @@ (f @@@ FactorInteger[n]); FoldList[Times, 1, Array[s, 31, 2]] (* Amiram Eldar, Dec 07 2020 *)

Crossrefs

Cf. A008833, A048803.

Sequence in context: A115639 A242954 A062732 * A309501 A024727 A024552

Adjacent sequences: A100774 A100775 A100776 * A100778 A100779 A100780

Keyword

easy,nonn

Author

Amarnath Murthy, Nov 28 2004

Extensions

More terms from Amiram Eldar, Dec 07 2020

Status

approved