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 A104179 #34 Oct 18 2024 18:13:06
%S A104179 2,3,5,7,23,37,53,73,223,233,337,353,373,523,733,773,2237,2333,3373,
%T A104179 3533,3733,5233,5237,5323,7333,7523,23333,23773,25237,32237,33533,
%U A104179 33773,35323,35353,37223,37337,52237,53233,53353,53773,73523,75323,77323
%N A104179 Primes that are either single-digit primes or a concatenation of two earlier terms.
%H A104179 Karl W. Heuer, <a href="/A104179/b104179.txt">Table of n, a(n) for n = 1..13849</a> (first 1003 terms from Jean-Marc Falcoz)
%F A104179 Up to 10^12 there are only 1003 terms and the n-th term seems to be roughly n^(10/e). - _Jean-Marc Falcoz_, Mar 28 2009
%F A104179 Although the n-th term does seem to be O(n^c), a better estimate for c is 4.38 rather than 10/e. The multiplier will be bounded but not convergent -- it jumps by a factor of 20/7 as we cross from a k-digit number beginning 777 to a (k+1)-digit number beginning 2222. - _Karl W. Heuer_, Sep 23 2024
%o A104179 (PARI) isDW(p,i=1)={while(p>i*=10,setminus(Set(divrem(p,i)),a)||return(eval(Set(Vec(Str(p)))[1])));p<9}
%o A104179 a=[]; forprime( p=2, 99999, isDW(p) & !print1(p",") & a=setunion(a,Set(p))) \\ _M. F. Hasler_, Mar 28 2009
%Y A104179 Cf. A376433 (number of n-digit terms), A376434 (smallest n-digit term), A376435 (largest n-digit term).
%K A104179 nonn,base
%O A104179 1,1
%A A104179 _David W. Wilson_, Mar 27 2009
%E A104179 More terms from _M. F. Hasler_, Mar 28 2009