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.
%I A289866 #24 May 12 2024 10:05:58
%S A289866 13,17,113,131,137,167,173,179,197,1103,1109,1151,1163,1181,1193,1223,
%T A289866 1229,1277,1283,1307,1367,1373,1409,1433,1439,1487,1499,1523,1571,
%U A289866 1601,1607,1613,1619,1709,1733,1787,1811,1823,1877,1907,1997,11069,11087,11093
%N A289866 Primes obtained from other primes by prefixing a 1.
%H A289866 Vincenzo Librandi, <a href="/A289866/b289866.txt">Table of n, a(n) for n = 1..2170</a>
%e A289866 131 is a term because it is a prime obtained by prefixing a 1 to the prime 31.
%e A289866 1409 is a term because it is a prime obtained by prefixing a 1 to the prime 409.
%t A289866 Select[Table[FromDigits[Join[IntegerDigits[1], IntegerDigits[Prime[n]]]], {n, 300}], PrimeQ]
%t A289866 Select[Table[10^IntegerLength[p]+p,{p,Prime[Range[200]]}],PrimeQ] (* _Harvey P. Dale_, Oct 17 2021 *)
%o A289866 (Magma) [k: p in PrimesUpTo(1500) | IsPrime(k) where k is Seqint(Intseq(p) cat [1])];
%Y A289866 Cf. A039790 (primes prefixed by 1).
%Y A289866 Cf. primes obtained from other primes by prefixing a k: this sequence (k=1), A165243 (k=2), A165292 (k=3), A165444 (k=4), A165555 (k=5), A289867 (k=6), A167187 (k=7), A290407 (k=8).
%K A289866 nonn,base
%O A289866 1,1
%A A289866 _Vincenzo Librandi_, Jul 14 2017