This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
Do[If[PrimeQ[10^n - Prime[n]], Print[n]], {n, 10800}]
is(n)=ispseudoprime(10^n-prime(n)) \\ Charles R Greathouse IV, May 15 2013
is(n)=isprime(10^n-n) \\ Charles R Greathouse IV, Feb 17 2017
from sympy import isprime
def afind(limit):
m, pow10 = 0, 1
while m <= limit:
if isprime(pow10 - m): print(m, end=", ")
m, pow10 = m + 1, pow10 * 10
afind(1000) # Michael S. Branicky, Mar 23 2021
/* The code gives only the terms up to 354: */ [n: n in [1..600] | IsPrime(10^n-2*n+1) ]
Select[Range[5000], PrimeQ[(10^# - 2 # + 1)] &] (* Vincenzo Librandi, Oct 05 2012 *)
is(n)=ispseudoprime(10^n-2*n+1) \\ Charles R Greathouse IV, Feb 20 2017
[n: n in [1..550] | IsPrime(10^n-2*n-1) ];
Select[Range[5000], PrimeQ[(10^# - 2*# - 1)] &] (* Vincenzo Librandi, Oct 05 2012 *)
for(n=1, 999, ispseudoprime(10^n-2*n-1) && print1(n", ")) \\ M. F. Hasler, Aug 06 2011
[n: n in [1..450] | IsPrime(10^n-DivisorSigma(1,n^2))]; // Vincenzo Librandi, Mar 26 2015
Select[Range[1000], PrimeQ[10^# - DivisorSigma[1, #^2]] &] (* Robert Price, Mar 24 2015 *)
for(n=1, 9999, ispseudoprime(t=10^n-sigma(n^2)) && print1(n", "))
for(n=1,999, ispseudoprime(t=10^n-prime(n)) && print1(t","))
Select[Range[0, 1000], PrimeQ[10^# + DivisorSigma[1, #^2]] &] (* Robert Price, May 08 2015 *)
for(n=1, 9999, ispseudoprime(10^n+sigma(n^2)) && print1(n", "))
4 is in this sequence since the fourth prime is 7 and 10^4+7=10007 is prime.
[n: n in [1..770] | IsPrime(NthPrime(n) + 10^n)]; // Vincenzo Librandi, Mar 30 2015
Select[Range[100000], PrimeQ[10^# + Prime[#]] &]
for(n=1,10^3,if(ispseudoprime(10^n+prime(n)),print1(n,", "))) \\ Derek Orr, Mar 29 2015
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