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 A032749 #23 Feb 16 2025 08:32:36 %S A032749 17546133,32613656,93568867,107225764,109255734,113315082,121251742, %T A032749 175461330,180917907,182557181,190215626,227366552,267791979, %U A032749 297981691,298002027,301321202,321541434,326136560,326687646,329178946,351038353 %N A032749 Super-9 Numbers (9*n^9 contains substring '999999999' in its decimal expansion). %C A032749 The smallest super-9 prime is 182557181. %C A032749 For any term a(n), all numbers a(n)*10^k, k >= 0, are also in the sequence. - _M. F. Hasler_, Jul 16 2024 %C A032749 Probably has density 1. In any case it has positive lower density since 10^12*k + 93568867 is in the sequence for all k > 0. This also shows there are infinitely many primes (with positive lower relative density in the primes) in this sequence. - _Charles R Greathouse IV_, Jul 17 2024 %D A032749 C. A. Pickover, "Keys to Infinity", New York: Wiley, p. 7, 1995. %H A032749 Giovanni Resta, <a href="https://www.numbersaplenty.com/set/super-d_number/">super-d numbers</a>, personal web site "Numbers Aplenty", 2013 %H A032749 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Super-dNumber.html">Super-d Number.</a> %e A032749 17546133^9 = 157627777777777302658446998030642098243159192883927973928032212853, and upon multiplication by 9, since 7...77*9 = 69...93, the string of 10 '7's becomes a string with 9 consecutive '9's. Hence 17546133 is in the sequence. %Y A032749 Cf. A014569, A032743-A032748. %K A032749 nonn,base %O A032749 1,1 %A A032749 _Patrick De Geest_, May 15 1998; extended Feb 22 2004