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 A144360 #20 Jul 24 2025 03:26:20 %S A144360 71,262151,1073741831,302231454903657293676551, %T A144360 85070591730234615865843651857942052871, %U A144360 23945242826029513411849172299223580994042798784118791,25711008708143844408671393477458601640355247900524685364822023 %N A144360 Primes of the form 8^k + 7. Also, primes of the form 64^m + 7. %C A144360 k=2m, since for odd k, 8^k + 7 is divisible by 3. %C A144360 Prime numbers p in A144242 such that p-1 is the fourth a-gonal and seventh b-gonal number for some a and b. Namely, a = (8^k+14)/6 and b = (8^k + 41)/21. %C A144360 This sequence appears to be a subset of A144313. %C A144360 The next term has 178 digits. - _Harvey P. Dale_, Sep 03 2015 %H A144360 Amiram Eldar, <a href="/A144360/b144360.txt">Table of n, a(n) for n = 1..10</a> %F A144360 a(n) = A253211(A217381(n)). - _Amiram Eldar_, Jul 23 2025 %e A144360 71 - 1 = 70 is the fourth triskaidecagonal number and seventh pentagonal number. %t A144360 Select[64^Range[40]+7,PrimeQ] (* _Harvey P. Dale_, Sep 03 2015 *) %o A144360 (Magma) [a: n in [0..80] | IsPrime(a) where a is 8^n+7]; // _Vincenzo Librandi_, Aug 02 2017 %Y A144360 Cf. A000040, A000668, A144231, A144232, A144233, A144234, A144236, A144242, A144245, A144246, A144247, A144313. %K A144360 nonn %O A144360 1,1 %A A144360 _Reikku Kulon_, Sep 18 2008 %E A144360 Edited by _Max Alekseyev_, Feb 17 2011