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 A334614 #37 Oct 04 2020 23:33:29 %S A334614 1,2,4,6,8,10,11,13,15,18,19,21,22,24,26,28,30,32,34,35,36,38,40,42, %T A334614 45,47,48,50,51,53,55,57,60,61,65,66,67,68,70,72,74,76,77,79,81,82,85, %U A334614 88,89,91,93,94,95,99,101,102,104,105,106,107,108,112,116,117 %N A334614 a(n) = pi(prime(n) - n) + n, where pi is the prime counting function. %C A334614 It can be shown that a(n) > a(n-1) >= 1 and a(n) <= 2*n - 1 < 2*n (see proofs in the Links section). %H A334614 Ya-Ping Lu, <a href="/A334614/a334614.pdf">Proofs of the two observations in the Comments section</a> %F A334614 a(n) = A000720(A014689(n)) + n. %F A334614 a(n) = A065328(n) + n. - _Michel Marcus_, Sep 12 2020 %t A334614 Table[PrimePi[Prime[n] - n] + n, {n, 1, 64}] (* _Amiram Eldar_, Sep 09 2020 *) %o A334614 (Python) %o A334614 from sympy import prime, primepi %o A334614 for n in range(1, 100001): %o A334614 a_n = primepi(prime(n) - n) + n %o A334614 print(a_n) %o A334614 (PARI) a(n) = n + primepi(prime(n) - n); \\ _Michel Marcus_, Sep 09 2020 %Y A334614 Cf. A000040, A000720, A014688, A014689, A062298, A065328, A097933. %Y A334614 Cf. A332086, A337334. %K A334614 nonn %O A334614 1,2 %A A334614 _Ya-Ping Lu_, Sep 08 2020