login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A212321 Minimal m >= 1 such that floor((2*n-1)!!/m) + 2 is prime. 5
1, 1, 1, 1, 1, 3, 9, 5, 5, 3, 1, 1, 7, 1, 13, 11, 15, 21, 23, 15, 17, 5, 25, 25, 7, 85, 9, 25, 1, 21, 9, 13, 17, 5, 49, 39, 45, 1, 43, 51, 145, 17, 143, 85, 19, 81, 63, 43, 47, 77, 23, 1, 3, 21, 17, 47, 37, 3, 7, 67, 23, 23, 25, 45, 81, 5, 39, 145, 71, 21, 41 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

LINKS

Table of n, a(n) for n=1..71.

MAPLE

a:= proc(n) local m;

      for m while not isprime(iquo(doublefactorial(2*n-1), m)+2)

      do od; m

    end:

seq(a(n), n=1..50);  # Alois P. Heinz, Feb 18 2013

CROSSREFS

Cf. A212281, A212282.

Sequence in context: A070341 A245719 A085851 * A306552 A092041 A317904

Adjacent sequences:  A212318 A212319 A212320 * A212322 A212323 A212324

KEYWORD

nonn

AUTHOR

Vladimir Shevelev, Feb 14 2013

EXTENSIONS

More terms from Alois P. Heinz, Feb 18 2013

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 19 00:12 EST 2019. Contains 329310 sequences. (Running on oeis4.)