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 A129487 #9 Feb 07 2019 23:48:50 %S A129487 1,2,3,4,5,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26, %T A129487 27,28,29,31,32,33,34,35,36,37,38,39,40,41,43,44,45,46,47,48,49,50,51, %U A129487 52,53,54,55,56,57,58,59,61,62,63,64,65,67,68,69,71,72,73,74,75,76,77,79 %N A129487 Unitary deficient numbers. %C A129487 The unitary deficient numbers account for almost 93% of all integers (including all primes (A000040) and prime powers (A000961)) and asymptotically satisfy a(n)~1.0753n. This provides an excellent fit as n grows larger. For example, the one millionth unitary deficient number is 1075293 and the asserted approximation returns 1075300, giving an error of only 0.00065%. %H A129487 Nathaniel Johnston, <a href="/A129487/b129487.txt">Table of n, a(n) for n = 1..10000</a> %F A129487 Integers for which A034460(n) < n, or equivalently for which A034448(n) < 2n. %e A129487 The sixth integer that exceeds the sum of its proper unitary divisors is 7. Hence a(6)=7. %p A129487 a := proc(n) numtheory[divisors](n); select(d -> igcd(d,n/d)=1,%); `if`(add(i,i=%) < 2*n,n,NULL) end: # _Peter Luschny_, May 03 2009 %t A129487 UnitaryDivisors[n_Integer?Positive]:=Select[Divisors[n],GCD[ #,n/# ]==1&];Select[Range[100],Plus@@UnitaryDivisors[ # ]-2#<0 &] %Y A129487 Cf. A034460, A034448, A129468, A034683, A000040, A000961. %K A129487 easy,nonn %O A129487 1,2 %A A129487 _Ant King_, Apr 20 2007