|
|
A352837
|
|
Primes p such that, if q is the next prime, p + q^2 is a prime times a power of 10.
|
|
4
|
|
|
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
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
Primes prime(k) such that when any trailing zeros are removed from A349660(k), the result is prime.
|
|
LINKS
|
|
|
EXAMPLE
|
a(3) = 709 is a term because 709 and 719 are consecutive primes, 709 + 719^2 = 517670, and 51767 is prime.
|
|
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;
|
|
MATHEMATICA
|
f[n_] := n/10^IntegerExponent[n, 10]; Select[Range[50000], PrimeQ[#] && PrimeQ[f[# + NextPrime[#]^2]] &] (* Amiram Eldar, Apr 07 2022 *)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|