A177926 a(n) = ((n-th-prime - 1)!)^2

1, 4, 576, 518400, 13168189440000, 229442532802560000, 437763136697395052544000000, 40990389067797283140009984000000, 1263377636044591724886240423994982400000000, 92956902680071188234494975268405495542386262016000000000000

Offset

1,2

Comments

Except first three terms, sqrt(a(n)/400) is an integer, also sqrt(a(n+1/a(n)) is an integer. [From Giovanni Teofilatto, May 16 2010]

Links

Table of n, a(n) for n=1..10.

Mathematica

((Prime[Range[10]]-1)!)^2 (* Harvey P. Dale, Apr 13 2014 *)

Crossrefs

Cf. A177771.

Sequence in context: A282196 A114764 A134372 * A241095 A343474 A177963

Adjacent sequences: A177923 A177924 A177925 * A177927 A177928 A177929

Keyword

easy,nonn

Author

Giovanni Teofilatto, May 15 2010

Extensions

One more term from Harvey P. Dale, Apr 13 2014

Status

approved