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 A284670 #30 May 09 2021 09:51:36 %S A284670 19,22,26,27,28,29,31,34,35,37,39,40,41,49,50,51,52,56,57,59,60,61,62, %T A284670 63,64,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86, %U A284670 87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104 %N A284670 Exponents of powers of 5 that contain all ten decimal digits. %C A284670 It is conjectured that a(n) = n + 40 for n > 25. %H A284670 Seiichi Manyama, <a href="/A284670/b284670.txt">Table of n, a(n) for n = 1..10000</a> %e A284670 5^19 = 19073486328125, which contains two 1's, two 2's, two 3's, one 4, one 5, one 6, one 7, two 8's, one 9 and one 0, so 19 is in the sequence. %t A284670 Select[Range[110], Union[IntegerDigits[5^#]] == Range[0, 9] &] (* _Indranil Ghosh_, Apr 01 2017 *) %o A284670 (PARI) isok(n) = #vecsort(digits(5^n),,8) == 10; \\ _Michel Marcus_, Apr 01 2017 %o A284670 (Python) %o A284670 from sympy.ntheory.factor_ import digits %o A284670 r10 = set(range(10)) %o A284670 print([n for n in range(1, 111) if set(sorted(digits(5**n)[1:])) == r10]) # _Indranil Ghosh_, Apr 01 2017 %Y A284670 Cf. A130694 (k=2), A236673 (k=3), this sequence (k=5). %K A284670 nonn,base %O A284670 1,1 %A A284670 _Seiichi Manyama_, Apr 01 2017