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 A281703 #10 Nov 12 2017 08:19:49 %S A281703 1,2,6,10,14,18,30,34,38,46,50,58,66,78,86,90,94,98,106,118,130,134, %T A281703 150,154,170,174,186,190,198,206,214,218,226,234,254,258,266,270,274, %U A281703 286,294,310,314,318,326,338,350,354,366,370,394,398,406,410,426,430 %N A281703 Numbers k such that A000005(k) = A000005(A000326(k)). %C A281703 Numbers k such that the number of divisors of k is equal to the number of divisors of the pentagonal number k*(3*k-1)/2. %H A281703 Colin Barker, <a href="/A281703/b281703.txt">Table of n, a(n) for n = 1..1000</a> %t A281703 Select[Range[500],DivisorSigma[0,#]==DivisorSigma[0,(#(3#-1))/2]&] (* _Harvey P. Dale_, Nov 12 2017 *) %o A281703 (PARI) select(k->numdiv(k)==numdiv(k*(3*k-1)/2), vector(500, k, k)) %Y A281703 Cf. A000005, A000326, A087370, A281702. %K A281703 nonn %O A281703 1,2 %A A281703 _Colin Barker_, Jan 28 2017