cp's OEIS Frontend

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.

A155762 Prime numbers p such that prepending any single decimal digit to p does not produce a prime.

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%I A155762 #22 May 29 2022 08:08:24
%S A155762 2,5,149,401,509,773,809,1021,1103,1289,1301,1451,1697,1709,1747,1877,
%T A155762 1889,2087,2389,2521,2663,3373,3511,3631,3733,3779,3821,3919,3947,
%U A155762 3989,4003,4073,4241,4289,4339,4637,4643,4801,4931,5039,5113,5387,5417,5477
%N A155762 Prime numbers p such that prepending any single decimal digit to p does not produce a prime.
%C A155762 149 is in the sequence, because the following numbers are all composite: 1149, 2149, 3149, 4149, 5149, 6149, 7149, 8149 and 9149.
%H A155762 Michael S. Branicky, <a href="/A155762/b155762.txt">Table of n, a(n) for n = 1..10000</a>
%t A155762 Select[Prime@Range@1000, NoneTrue[#+10^IntegerLength@#*Range@9, PrimeQ]&] (* _Hans Rudolf Widmer_, May 28 2022 *)
%o A155762 (Python)
%o A155762 from sympy import isprime, primerange
%o A155762 def ok(p): return not any(isprime(int(d+str(p))) for d in "123456789")
%o A155762 print(list(filter(isprime, primerange(2, 5500)))) # _Michael S. Branicky_, May 28 2022
%Y A155762 Cf. A119289.
%K A155762 nonn,base
%O A155762 1,1
%A A155762 _Dmitry Kamenetsky_, Jan 26 2009