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 A370125 #9 Feb 21 2024 22:49:32 %S A370125 1,6,9,14,15,21,25,26,33,35,38,39,49,50,51,55,57,62,65,69,74,77,81,85, %T A370125 86,87,91,93,95,110,111,115,119,121,122,123,129,133,134,135,141,143, %U A370125 145,146,155,158,159,161,169,170,177,183,185,187,189,194,201,203,205,206,209,213,215,217,218,219,221,225,230,235 %N A370125 Numbers k such that the least prime dividing the arithmetic derivative of k is equal to the least prime not dividing k. %H A370125 Antti Karttunen, <a href="/A370125/b370125.txt">Table of n, a(n) for n = 1..10000</a> %e A370125 The initial term 1 is included because A003415(1) = 0, every prime divides zero, including the smallest of primes, which is 2, and 2 is also the least prime that does not divide 1. %e A370125 6 = 2*3 is included because the smallest prime that does not divide it is 5, and 5 is also the smallest prime dividing 6' = 5. %e A370125 14 = 2*7 is included because the smallest prime dividing 14' = 2+7 = 9 is 3, which is also the smallest prime not dividing 14. %o A370125 (PARI) \\ See A370124. %Y A370125 Cf. A003415, A020639, A053669, A276086, A370124 (characteristic function). %Y A370125 Cf. A016754 (subsequence). %K A370125 nonn %O A370125 1,2 %A A370125 _Antti Karttunen_, Feb 21 2024