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A215028 a(1) = 1; for n >= 1, a(n+1) = (concatenation of n+1 and n) - a(n). 2

%I #11 Jan 22 2021 15:44:34

%S 1,20,12,31,23,42,34,53,45,64,1046,165,1147,266,1248,367,1349,468,

%T 1450,569,1551,670,1652,771,1753,872,1854,973,1955,1074,2056,1175,

%U 2157,1276,2258,1377,2359,1478,2460,1579,2561,1680,2662,1781,2763,1882,2864,1983

%N a(1) = 1; for n >= 1, a(n+1) = (concatenation of n+1 and n) - a(n).

%C A variation of A215027.

%p f:=proc(i) (i+1)*10^(1+floor(evalf(log10(i))))+i; end: # A127423

%p a:=proc(n) option remember; global f; if n=1 then 1 else f(n-1)-a(n-1); fi; end;

%o (PARI) A215028(n, print_all=0)={my(a=1); for(n=1, n-1, print_all & print1(a","); a=(n+1)*10^#Str(n)+n-a); a} \\ _M. F. Hasler_, Aug 23 2012

%Y Cf. A215027, A127423.

%K nonn,base

%O 1,2

%A _N. J. A. Sloane_, Aug 04 2012

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Last modified March 29 02:23 EDT 2024. Contains 371264 sequences. (Running on oeis4.)