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A110756 a(n) = tau(N), where N = concatenation 1,2,3,...,n. 6

%I #18 Feb 13 2023 15:56:31

%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

%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

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Last modified March 29 05:28 EDT 2024. Contains 371264 sequences. (Running on oeis4.)