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A083678 Numbers n = d_1 d_2 ... d_k (in base 10) with properties that k is even and d_i + d_{k+1-i} = 10 for all i. 2

%I

%S 19,28,37,46,55,64,73,82,91,1199,1289,1379,1469,1559,1649,1739,1829,

%T 1919,2198,2288,2378,2468,2558,2648,2738,2828,2918,3197,3287,3377,

%U 3467,3557,3647,3737,3827,3917,4196,4286,4376,4466,4556,4646,4736,4826,4916

%N Numbers n = d_1 d_2 ... d_k (in base 10) with properties that k is even and d_i + d_{k+1-i} = 10 for all i.

%C The two-digit terms here occur in many sequences, e.g. A066686, A081926, A017173, A030108, A043457, A052224, A061388, A084364.

%e 1469 and 6284 are members because 1+9=4+6=10 and 6+4=2+8=10.

%o (PARI) isok(n) = {digs = digits(n); if (#digs % 2 == 0, for (i = 1, #digs/2, if ((digs[i] + digs[#digs+1-i]) ! = 10, return (0));); return (1);); return (0);} \\ _Michel Marcus_, Oct 05 2013

%Y Cf. A066686, A081926, A017173, A030108, A043457, A052224, A061388, A084364.

%K easy,nonn,base

%O 1,1

%A _Zak Seidov_ Jun 15 2003

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Last modified July 24 14:48 EDT 2021. Contains 346273 sequences. (Running on oeis4.)