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 A182178 #25 Nov 01 2014 20:45:35
%S A182178 1,2,3,4,7,6,5,8,9,20,21,11,12,14,16,50,23,25,29,41,43,47,49,83,85,61,
%T A182178 65,67,411,111,112,30,32,34,38,52,56,58,92,94,70,74,76,114,98,302,116,
%U A182178 120,202,121,123,89,203,205,207,412,125,211,129,212,141,143
%N A182178 Beginning with 1, smallest positive integer not yet in the sequence such that two adjacent digits of the sequence (also ignoring commas between terms) sum to a prime.
%C A182178 See A219110 for the numbers which do not occur in this sequence. See A219250 for the analog when "sum" is replaced with "absolute difference", and A219248-A219251 for related sequences. - _M. F. Hasler_, Apr 11 2013
%H A182178 Zak Seidov, <a href="/A182178/b182178.txt">Table of n, a(n) for n = 1..10000</a>
%e A182178 20 follows 9 since 9+2 and 2+0 is prime, and no number less than 20 (not already in the sequence) satisfies the stated property.
%t A182178 a[1] = 1; a[n_] := a[n] = For[id = IntegerDigits[a[n-1]]; k = 1, True, k++, If[FreeQ[Array[a, n-1], k], dd = Join[id, IntegerDigits[k]]; If[And @@ PrimeQ /@ Plus @@@ Transpose[{Most[dd], Rest[dd]}], Return[k]]]]; Array[a, 62] (* _Jean-François Alcover_, Apr 17 2013 *)
%o A182178 (PARI) A182178_vec={(n, a=[1], u=0)->while(#a<n, u+=1<<a[#a]; for(t=a[1]+1, 9e9, bittest(u, t)&next; my(d=concat(a[#a]%10, digits(t))); for(i=2, #d, isprime(d[i-1]+d[i])||next(2)); a=concat(a, t); break)); a} \\ _M. F. Hasler_, Apr 11 2013
%Y A182178 Cf. A182175, A182177.
%K A182178 nonn,base,easy
%O A182178 1,2
%A A182178 _Jim Nastos_ and _Eric Angelini_, Apr 16 2012