A258080 - OEIS

%I #15 Jun 06 2015 11:53:48

%S 1,1,5,19,1,17,53,43,29,31,79,29,179,199,11,69,169,317,139,361,185,

%T 497,331,149,601,439,263,73,739,581,411,229,35,1019,871,713,545,367,

%U 179,1621,1495,1361,1219,1069,911,745,571,389,199,1,2447,2337,2221,2099

%N a(n) = ((n concatenated with n+1) + (n+1 concatenated with n)) mod n*(n+1).

%H Peter J. C. Moses, <a href="/A258080/b258080.txt">Table of n, a(n) for n = 1..2000</a>

%t Map[Mod[FromDigits[Flatten[{#1,#2}]]+FromDigits[Flatten[{#2,#1}]]&[IntegerDigits[#+1],IntegerDigits[#]],# (#+1)]&,Range[100]] (*_Peter J. C. Moses_, May 19 2015*)

%o (PARI) a(n) = (eval(concat(Str(n), Str(n+1))) + eval(concat(Str(n+1), Str(n)))) % (n*(n+1)); \\ _Michel Marcus_, Jun 04 2015

%Y Cf. A001704 (concatenation {n,n+1}).

%K nonn,base

%O 1,3

%A _Vladimir Shevelev_, May 19 2015

%E More terms from _Peter J. C. Moses_, May 19 2015