A352837 Primes p such that, if q is the next prime, p + q^2 is a prime times a power of 10.
2, 409, 709, 1249, 3229, 4621, 6709, 7069, 7129, 7489, 8209, 9241, 9661, 10789, 11149, 13381, 13789, 15349, 17509, 20641, 21169, 21961, 23509, 25819, 26449, 28309, 28729, 32029, 32089, 34849, 35089, 35809, 37321, 37369, 39769, 40129, 42169, 42349, 42709, 42901, 42979, 44179, 46489, 47269, 47809
Offset: 1
Keywords
Examples
a(3) = 709 is a term because 709 and 719 are consecutive primes, 709 + 719^2 = 517670, and 51767 is prime.
Links
- Robert Israel, Table of n, a(n) for n = 1..10000
Programs
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Maple
R:= NULL: count:= 0: q:= 2: while count < 100 do p:= q; q:= nextprime(p); v:= p+q^2; if v mod 10 = 0 then v:= v/10^min(padic:-ordp(v,2),padic:-ordp(v,5)) fi; if isprime(v) then count:= count+1; R:= R,p; fi; od: R;
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Mathematica
f[n_] := n/10^IntegerExponent[n, 10]; Select[Range[50000], PrimeQ[#] && PrimeQ[f[# + NextPrime[#]^2]] &] (* Amiram Eldar, Apr 07 2022 *)
Comments