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 A069616 #4 May 21 2025 18:58:55 %S A069616 4,41,241,2411,32411,324113,6324113,63241133,1563241133,15632411339, %T A069616 815632411339,81563241133919,281563241133919,2815632411339191, %U A069616 322815632411339191,32281563241133919151,432281563241133919151 %N A069616 a(1) = 4; a(2n) = smallest prime that is a right concatenation of a(2n-1) and a number with no insignificant zeros and a(2n+1) = smallest prime ending in ( the least significant digits) a(2n-1). Alternate left and right concatenation yielding primes. %e A069616 a(4) = 2411 starting with a(3) =241 and a(5) = 32411 ending in a(4) = 2411. %Y A069616 Cf. A053582, A069605, A069606, A069607, A069608, A069609, A069610, A069611, A069613, A069614, A069615. %K A069616 nonn,base %O A069616 1,1 %A A069616 _Amarnath Murthy_, Mar 27 2002 %E A069616 More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Mar 30 2003