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 A210706 #22 Apr 03 2023 10:36:13 %S A210706 23,80,2487 %N A210706 Numbers k such that floor[ 3^(1/3)*10^k ] is prime. %C A210706 Inspired by prime curios about 4957 (cf. LINKS), one of which honors the late Bruce Murray (Nov 30 1931 - Aug 29 2013). %C A210706 Meant to be a "condensed" version of A210704, see there for more. %C A210706 Alternate definition: Numbers k such that concatenation of the first (k+1) digits of A002581 yields a prime. %H A210706 C. Caldwell, G. L. Honaker (Eds.), <a href="https://t5k.org/curios/page.php?short=4957">4957 (another Prime Pages' Curiosity)</a>. %F A210706 a(n) = (length of A210704(n)) - 1, where "length" means number of decimal digits. %e A210706 t = 3^(1/3) = 1.44224957030740838232163831... multiplied by 10^23 yields %e A210706 t*10^23 = 144224957030740838232163.831..., the integer part of which is the prime A210704(1), therefore a(1)=23. %o A210706 (PARI) \p2999 %o A210706 t=sqrtn(3,3);for(i=1,2999,ispseudoprime(t\.1^i)&print1(i",")) %Y A210706 Cf. A002581 = decimal expansion of 3^(1/3). %Y A210706 Cf. A065815 (analog for gamma), A060421 (1+ analog for Pi), A064118 (1+ analog for exp(1)), A119344 (1 + analog for sqrt(3)), A136583 (1+ analog for sqrt(10)). %K A210706 nonn,base,more,bref %O A210706 1,1 %A A210706 _M. F. Hasler_, Aug 31 2013