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URL: https://oeis.org/A236249

⇱ A236249 - OEIS

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A236249
Primes of the form C(2*m, m) - prime(m), where C(2*m, m) = (2*m)!/(m!)^2.
5
3, 241, 911, 184727, 30067266499540931, 1454272161238683681127450712107767894181359647011258114106151524833563647084221
OFFSET
1,1
COMMENTS
Though the primes in this sequence are very rare, according to the conjecture in A236256 there should be infinitely many such primes.
See A236248 for a list of known numbers m with C(2*m, m) - prime(m) prime.
See also A236245 for a similar sequence.
LINKS
EXAMPLE
a(1) = 3 since C(2*1, 1) - prime(1) = 0 is not prime, but C(2*2, 2) - prime(2) = 6 - 3 = 3 is prime.
MATHEMATICA
t[n_]:=Binomial[2n, n]-Prime[n]
a[n_]:=t[A234248(n)]
Table[a[n], {n, 1, 6}]
KEYWORD
nonn
AUTHOR
Zhi-Wei Sun, Jan 21 2014
STATUS
approved