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A348477 Drop all 1 but the first 1 in A035306.

%I A348477 #36 Oct 22 2021 23:24:57
%S A348477 1,2,3,2,2,5,2,3,7,2,3,3,2,2,5,11,2,2,3,13,2,7,3,5,2,4,17,2,3,2,19,2,
%T A348477 2,5,3,7,2,11,23,2,3,3,5,2,2,13,3,3,2,2,7,29,2,3,5,31,2,5,3,11,2,17,5,
%U A348477 7,2,2,3,2,37,2,19,3,13,2,3,5,41,2,3,7,43,2,2,11,3,2,5,2,23,47,2,4,3,7,2,2,5,2,3,17,2,2,13,53,2,3,3,5,11,2,3,7,3,19,2,29
%N A348477 Drop all 1 but the first 1 in A035306.
%C A348477 List of prime divisors of n and their exponents, ignoring the exponent 1. - _Michael De Vlieger_, Oct 20 2021
%H A348477 Seiichi Manyama, <a href="/A348477/b348477.txt">Table of n, a(n) for n = 1..10000</a>
%H A348477 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PrimeFactorization.html">Prime Factorization</a>.
%e A348477    n   prime factorization  triangle
%e A348477    1 = 1.                 ->  1;
%e A348477    2 = 2.                 ->  2;
%e A348477    3 = 3.                 ->  3;
%e A348477    4 = 2^2.               ->  2, 2;
%e A348477    5 = 5.                 ->  5;
%e A348477    6 = 2*3.               ->  2, 3;
%e A348477    7 = 7.                 ->  7;
%e A348477    8 = 2^3.               ->  2, 3;
%e A348477    9 = 3^2.               ->  3, 2;
%e A348477   10 = 2*5.               ->  2, 5;
%e A348477   11 = 11.                -> 11;
%e A348477   12 = 2^2*3.             ->  2, 2, 3;
%e A348477   13 = 13.                -> 13;
%e A348477   14 = 2*7                ->  2, 7;
%e A348477   15 = 3*5.               ->  3, 5;
%e A348477   16 = 2^4.               ->  2, 4;
%t A348477 Array[DeleteCases[Flatten@ FactorInteger[#], 1] &, 58] /. {} -> {1} // Flatten (* _Michael De Vlieger_, Oct 20 2021 *)
%o A348477 (PARI)
%o A348477 tabf(nn) = if(nn==1, print1(1, ", "), my(f=factor(nn)); for(i=1, #f~, for(j=1, 2, if((k=f[i, j])>j-1, print1(k, ", ")))));
%o A348477 (Ruby)
%o A348477 require 'prime'
%o A348477 def A348477(n)
%o A348477   ary = (2..n).map{|i| i.prime_division}.flatten
%o A348477   ary.delete(1)
%o A348477   [1] + ary
%o A348477 end
%o A348477 p A348477(60)
%Y A348477 Column 1 is A020639.
%Y A348477 Row lengths are A238949(n) for n > 1.
%Y A348477 Cf. A027746, A035306.
%K A348477 nonn,easy,tabf
%O A348477 1,2
%A A348477 _Seiichi Manyama_, Oct 20 2021