%I #22 Apr 01 2024 16:26:23
%S 1,6,4,4,8,28,4,24,12,8,64,32,8,8,8,12,24,48,64,192,256,64,16,48,24,
%T 160,96,64,16,128,8,48,64,4,192,120,16,16,64,384,32,128,16,48,768,128,
%U 32,192,64,768,8,32,64,1792,32,24,64,16,16,128,8,192,24,768,64
%N a(n) = tau(N), where N = concatenation 1,2,3,...,n.
%H Tyler Busby, <a href="/A110756/b110756.txt">Table of n, a(n) for n = 1..117</a>
%F a(n) = A000005(A007908(n)). - _R. J. Mathar_, Feb 10 2007
%e a(3) = tau(123) = 4.
%p A055642 := proc(n) 1+floor(log10(n)) ; end; A000005 := proc(n) numtheory[tau](n) ; end ; A007908 := proc(n) local a ; a := 1 ; for i from 2 to n do a := a*10^A055642(i)+i ; end; RETURN(a) ; end; A110756 := proc(n) A000005(A007908(n)) ; end; for n from 1 to 50 do printf("%d %d ",n,A110756(n)) ; od ; # _R. J. Mathar_, Feb 10 2007
%t Table[DivisorSigma[0,FromDigits[Flatten[IntegerDigits/@Range[n]]]],{n,60}] (* _Harvey P. Dale_, Apr 01 2024 *)
%Y Cf. A000005, A007908, A110757, A110758, A110759, A110760.
%K nonn,base
%O 1,2
%A _Amarnath Murthy_, Aug 11 2005
%E More terms from _R. J. Mathar_, Feb 10 2007
%E More terms from _David Wasserman_, Dec 22 2008
%E a(57)-a(65) from _Jinyuan Wang_, May 23 2020