Search: id:A103445
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%I A103445
%S A103445 1,2,4,6,10,14,22,22,30,46,74,94,90,102,130,170,198,222,290,350,474,650,
%T A103445 730,734,746,838,962,1214,2138,2582,1890,1830,2526,3498,4746,6842,5098,
%U A103445 6358,8178,10634,8650,9782,13634,14438,17178,20202,22170,21422,16298
%N A103445 Sum of the numbers of unitary divisors of the binomial coefficients C[n,
               k], k=0..n.
%C A103445 Row sums of the triangle A103444.
%e A103445 a(3)=6 because the divisors of 1,3,3,1 are {1},{1,3},{1,3},{1}, respectively, 
               all of which are unitary.
%p A103445 with(numtheory):unitdiv:=proc(n) local A, k: A:={}: for k from 1 to tau(n) 
               do if gcd(divisors(n)[k],n/divisors(n)[k])=1 then A:=A union {divisors(n)[k]} 
               else A:=A fi od end: T:=proc(n,k) if k<=n then nops(unitdiv(binomial(n,
               k))) else 0 fi end: for n from 0 to 50 do b[n]:=[seq(T(n,k),k=0..n)] 
               od: seq(sum(b[n][j],j=1..n+1),n=0..50);
%Y A103445 Cf. A103444.
%Y A103445 Sequence in context: A136460 A000065 A023499 this_sequence A001747 A048670 
               A077625
%Y A103445 Adjacent sequences: A103442 A103443 A103444 this_sequence A103446 A103447 
               A103448
%K A103445 nonn
%O A103445 0,2
%A A103445 Emeric Deutsch (deutsch(AT)duke.poly.edu), Feb 06 2005

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