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 A073628 #19 Jun 03 2025 02:54:45 %S A073628 0,1,2,4,5,8,10,11,16,20,23,24,26,29,34,38,41,48,50,51,56,60,63,68,80, %T A073628 81,90,92,95,96,102,109,120,124,129,130,138,141,142,148,149,152,156, %U A073628 159,164,168,171,182,188,193,196,198,199,202,206,209,216,218,219,222,232 %N A073628 a(0) = 0; a(1) = 1; a(2) = 2; a(n) = smallest number greater than the previous term such that the sum of three successive terms is a prime. %C A073628 Slowest increasing sequence where 3 consecutive integers sum up to a prime. %C A073628 In a string there can be at most two consecutive integers, e.g., (10, 11). More generally, three consecutive terms cannot be in arithmetic progression. %H A073628 Harvey P. Dale, <a href="/A073628/b073628.txt">Table of n, a(n) for n = 0..1000</a> %e A073628 0 + 1 + 2 = 3, which is prime; 1 + 2 + 4 = 7, which is prime; 2 + 4 + 5 = 11, which is prime. %t A073628 n1 = 0; n2 = 1; counter = 1; maxnumber = 10^4; Do[ If[PrimeQ[n1 + n2 + n], {sol[counter] = n; counter = counter + 1; n1 = n2; n2 = n}], {n, 2, maxnumber}]; Table[sol[j], {j, 1, counter}] (* Ben Ross (bmr180(AT)psu.edu), Jan 29 2006 *) %t A073628 nxt[{a_,b_,c_}]:={b,c,Module[{x=c+1},While[!PrimeQ[b+c+x],x++];x]}; Transpose[ NestList[nxt,{0,1,2},60]][[1]] (* _Harvey P. Dale_, Jun 10 2013 *) %Y A073628 Cf. A073627. %K A073628 nonn %O A073628 0,3 %A A073628 _Amarnath Murthy_, Aug 08 2002 %E A073628 More terms from _Matthew Conroy_, Sep 09 2002 %E A073628 Entry revised by _N. J. A. Sloane_, Mar 25 2007