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 A154981 #14 Mar 29 2014 05:21:52 %S A154981 11,13,17,19,31,41,47,61,67,71,89,101,103,107,109,113,127,131,137,139, %T A154981 149,151,157,163,167,173,179,181,191,193,197,199,211,241,251,271,281, %U A154981 307,311,313,317,331,401,409,419,421,431,449,457,461,467,479,487,491 %N A154981 Primes with nonprime smallest digit. %C A154981 Nonprime digits in base 10 are 0, 1, 4, 6, 8 and 9. %H A154981 Vincenzo Librandi, <a href="/A154981/b154981.txt">Table of n, a(n) for n = 1..1000</a> %e A154981 17 is in the sequence because its smallest digit is 1, which is not prime. %e A154981 19 is in the sequence because its smallest digit is 1, which is not prime (neither is 9, for that matter). %e A154981 23 is not in the sequence because both of its digits are prime. %t A154981 Select[Prime[Range[150]], Not[PrimeQ[Min[IntegerDigits[#]]]] &] (* _Alonso del Arte_, Mar 28 2014, based on _Harvey P. Dale_'s program for A155053 *) %Y A154981 Cf. A019546, A020457, A141468. %K A154981 nonn,base %O A154981 1,1 %A A154981 _Juri-Stepan Gerasimov_, Jan 19 2009 %E A154981 Entries checked by _R. J. Mathar_, Mar 29 2010