cp's OEIS Frontend

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.

A327786 Numbers whose number of distinct prime factors is greater than the sum of their digits.

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%I A327786 #28 Sep 08 2022 08:46:24
%S A327786 10,100,110,210,1000,1001,1010,1020,1100,1110,2010,2100,10000,10010,
%T A327786 10020,10100,10101,10110,10200,11000,11010,11100,20010,20020,20100,
%U A327786 21000,100000,100002,100010,100011,100020,100100,100110,100200,101000,101010,101100,102000
%N A327786 Numbers whose number of distinct prime factors is greater than the sum of their digits.
%C A327786 The sequence is infinite since every number of the form 10^k for k >= 1 is in the sequence. It can be proved that 210 is the largest term with distinct digits.
%H A327786 Giovanni Resta, <a href="/A327786/b327786.txt">Table of n, a(n) for n = 1..10000</a> (first 291 terms from Metin Sariyar)
%e A327786 For a(4) = 210, 2 + 1 + 0 = 3, 210 = 2*3*5*7 with 4 distinct factors, 4 > 3 so 210 is a term.
%t A327786 Select[Range[10^6], Total[IntegerDigits[#]]<Length[FactorInteger[#]]&]
%t A327786 Select[Range[120000],PrimeNu[#]>Total[IntegerDigits[#]]&] (* _Harvey P. Dale_, Jul 07 2020 *)
%o A327786 (PARI) isok(n) = omega(n) > sumdigits(n); \\ _Michel Marcus_, Sep 25 2019
%o A327786 (Magma) [k:k in [2..110000]| #PrimeDivisors(k) gt &+Intseq(k)]; // _Marius A. Burtea_, Oct 07 2019
%Y A327786 Cf. A001221, A165256.
%K A327786 nonn,base
%O A327786 1,1
%A A327786 _Metin Sariyar_, Sep 25 2019