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Row sums of A099884, the XOR difference triangle of the powers of 2.
1

%I #2 Mar 30 2012 18:37:16

%S 1,5,15,45,107,265,615,1485,3227,7225,15735,35325,75019,163145,348135,

%T 761805,1589147,3374905,7077495,15138045,31390219,66122825,137816295,

%U 292344525,601532059,1253593145,2591401335,5435447805,11157226763

%N Row sums of A099884, the XOR difference triangle of the powers of 2.

%e Triangle A099884 begins:

%e 1;

%e 2, 3;

%e 4, 6, 5;

%e 8, 12, 10, 15;

%e 16, 24, 20, 30, 17;

%e 32, 48, 40, 60, 34, 51;

%e 64, 96, 80, 120, 68, 102, 85;

%e 128, 192, 160, 240, 136, 204, 170, 255;

%e 256, 384, 320, 480, 272, 408, 340, 510, 257; ...

%e where terms in any column are formed from the XOR operation between

%e adjacent terms of the prior column, with column 0 being powers of 2.

%o (PARI) {a(n)=local(B,RS=0); for(k=0,n, B=0; for(i=0, k, B=bitxor(B, binomial(k, i)%2*2^(n-i))); RS+=B);RS}

%Y Cf. A099884.

%K nonn

%O 0,2

%A _Paul D. Hanna_, Apr 11 2009