A066749 List of primes p which are equal to a central binomial coefficient C(n,floor(n/2)) plus 1.
2, 3, 7, 11, 71, 127, 463, 3433, 2704157, 20058301, 17672631901, 35345263801, 2104098963721, 16123801841551, 6892620648693261354601, 51913710643776705684835561, 410795449442059149332177041, 12738806129490428451365214301, 760401738905937245009910944207609329
Offset: 1
Keywords
Examples
For n=5 the central binomial coefficient is C(5,2)=10. Since 10+1=11 is prime, it is in the sequence.
Links
- Harvey P. Dale, Table of n, a(n) for n = 1..53 (The next term, a(54), has 1244 digits.)
Programs
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Mathematica
For[ n=0, True, n++, If[ PrimeQ[ z=Binomial[ n, Floor[ n/2 ] ]+1 ], Print[ z ] ] ] Select[Table[1+Binomial[n,Floor[n/2]],{n,100}],PrimeQ] (* Harvey P. Dale, Nov 24 2018 *) -
MuPAD
for n from 0 to 200 do p := binomial(n,floor(n/2))+1: if isprime(p) then print(p) end_if end_for
Extensions
Repetitions removed by N. J. A. Sloane, Apr 09 2008
More terms from Harvey P. Dale, Nov 24 2018
Comments