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 A168219 #16 Jan 26 2021 10:50:45 %S A168219 1,3,4,6,15,16,18,24,27,30,31,36,37,43,51,52,57,60,73,75,81,82,87,90, %T A168219 93,106,108,109,114,145,154,159,160,163,165,171,174,175,178,196,201, %U A168219 204,207,208,211,220,222,225,228,234 %N A168219 Naturals n for which 1 + 10*n^3 (A168147) is prime. %C A168219 It is conjectured that sequence is infinite. %C A168219 No three consecutive integers n are in the list. [Proof: An integer of the form n=3*k+2 generates 1+10*n^3 = 9*(9+30*k^3+60*k^2+40*k) which is divisible through 9, hence not a prime, so these n are not in the list. Since every third integer is of this form == 2 (mod 3), no more than two consecutive integers can be in the sequence.] [_Zak Seidov_, Nov 24 2009] %D A168219 Harold Davenport, Multiplicative Number Theory, Springer-Verlag New-York 1980. %D A168219 Leonard E. Dickson: History of the Theory of numbers, vol. I, Dover Publications 2005. %D A168219 Paulo Ribenboim, The New Book of Prime Number Records, Springer 1996. %H A168219 G. C. Greubel, <a href="/A168219/b168219.txt">Table of n, a(n) for n = 1..1139</a> %e A168219 (1) 1+10*1^3=11 gives a(1)=1 %e A168219 (2) 1+10*3^3=271=3^4 gives a(2)=3 %e A168219 (3) 1+10*37^3=506531 gives a(13)=37 %t A168219 Select[Range[100], PrimeQ[1 + 10*#^3] &] (* _G. C. Greubel_, Jul 16 2016 *) %o A168219 (PARI) for(n=1,2e2, isprime(n^3*10+1) && print1(n", ")) \\ _M. F. Hasler_, Jul 24 2011 %Y A168219 Cf. A000040, A168147, A167535. %K A168219 nonn %O A168219 1,2 %A A168219 Eva-Maria Zschorn (e-m.zschorn(AT)zaschendorf.km3.de), Nov 20 2009