A175913 Convert to decimal the number resulting from performing binary xnor on the corresponding digits in the left and right binary concatenations of the integers one to n.

1, 4, 25, 190, 1159, 15692, 111381, 1416474, 24608235, 291074808, 5162763209, 125052555486, 2198977618351, 28389504497340, 487294161504141, 11589641752262546, 395151697837143155, 13197172619557324880

Offset

1,2

Links

Table of n, a(n) for n=1..18.

Mathematica

frombinrep[x_] := FromDigits[Flatten[Table[Table[If[OddQ[ n], 1, 0], {d, 1, x[[n]]}], {n, 1, Length[x]}]], 2]
repcount[x_] := Length/@Split[x]
l = {}; r = {}; Table[d = IntegerDigits[x, 2]; l = Flatten[{l, d}]; r = Flatten[{d, r}]; frombinrep[ repcount[EvenQ[l + r]]], {x, 1, DESIRED NUMBER OF TERMS HERE}]

Crossrefs

Cf. A047778, A098780

Sequence in context: A135147 A221382 A215791 * A239996 A064063 A171991

Adjacent sequences: A175910 A175911 A175912 * A175914 A175915 A175916

Keyword

base,easy,nonn

Author

Dylan Hamilton, Oct 14 2010

Status

approved