A214078 a(n) = (ceiling (sqrt(n)))!.

1, 1, 2, 2, 2, 6, 6, 6, 6, 6, 24, 24, 24, 24, 24, 24, 24, 120, 120, 120, 120, 120, 120, 120, 120, 120, 720, 720, 720, 720, 720, 720, 720, 720, 720, 720, 720, 5040, 5040, 5040, 5040, 5040, 5040, 5040, 5040, 5040, 5040, 5040, 5040, 5040, 40320, 40320, 40320

Offset

0,3

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Formula

a(n) = A000142(A003059(n)). - Michel Marcus, Jul 28 2022

Sum_{n>=0} 1/a(n) = e + 2. - Amiram Eldar, Aug 15 2022

Mathematica

Table[Ceiling[Sqrt[n]]!, {n, 0, 50}] (* T. D. Noe, Dec 23 2012 *)

Prog

(Derive) PROG(y := [], n := 50, LOOP(IF(n = -1, RETURN y), y := ADJOIN(CEILING(SQRT(n))!, y), n := n - 1))
(Magma) [Factorial(Ceiling (Sqrt(n))): n in [0..50]]; // Vincenzo Librandi, Feb 13 2013
(PARI) a(n) = ceil(sqrt(n))!; \\ Altug Alkan, Jan 11 2016
(Python)
from math import factorial, isqrt
def A214078(n): return factorial(1+isqrt(n-1)) if n else 1 # Chai Wah Wu, Jul 28 2022

Crossrefs

Cf. A214078, A214079, A214080, A214081, A214083, A055228, A055226.

Cf. A000142, A003059.

Sequence in context: A171698 A339385 A080969 * A155453 A032558 A211512

Adjacent sequences: A214075 A214076 A214077 * A214079 A214080 A214081

Keyword

easy,nonn

Author

Mohammad K. Azarian, Dec 22 2012

Status

approved