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 A095862 #23 Dec 27 2023 11:55:26 %S A095862 1,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97,121, %T A095862 169,289,361,529,841,961,1003,1006,1007,1011,1018,1027,1037,1041,1042, %U A095862 1043,1046,1047,1055,1057,1059,1067,1073,1077,1079,1081,1082,1094,1099 %N A095862 Numbers whose number of decimal digits and number of divisors are equal. %C A095862 An element of this sequence is prime iff it has 2 digits, which is the case for a(2)=11 through a(22); sequence A096489 lists exactly these and the leading term a(1)=1 (the only noncomposite number which is not prime). - _M. F. Hasler_, Nov 29 2007 %H A095862 Alois P. Heinz, <a href="/A095862/b095862.txt">Table of n, a(n) for n = 1..10000</a> %p A095862 q:= n-> is(length(n)=numtheory[tau](n)): %p A095862 select(q, [$1..1100])[]; # _Alois P. Heinz_, Jun 18 2021 %t A095862 Select[Range[1100],IntegerLength[#]==DivisorSigma[0,#]&] (* _Harvey P. Dale_, Oct 19 2015 *) %Y A095862 Cf. A096489 (= a(1)..a(22) = noncomposite elements of this sequence). %Y A095862 Cf. A135772-A135779 (analog for bases 2...9). %K A095862 base,nonn %O A095862 1,2 %A A095862 _Ray Chandler_, Jun 28 2004 %E A095862 Edited by _M. F. Hasler_, Nov 29 2007