OFFSET
0,4
LINKS
Michael De Vlieger, Table of n, a(n) for n = 0..10000
MAPLE
# From A014081:
cn := proc(v, k) local n, s, nn, i, j, som, kk;
som := 0;
kk := convert(cat(seq(1, j = 1 .. k)), string);
n := convert(v, binary);
s := convert(n, string);
nn := length(s);
for i to nn - k + 1 do
if substring(s, i .. i + k - 1) = kk then som := som + 1 fi od;
som; end;
[seq(n-cn(n, 1)+cn(n, 2)-cn(n, 3), n=0..100)];
MATHEMATICA
cn[n_, k_] := Count[Partition[IntegerDigits[n, 2], k, 1], Table[1, {k}]]; Table[n - Sum[cn[n, i], {i, 1, 3, 2}] + cn[n, 2], {n, 0, 77}] (* Michael De Vlieger, Sep 18 2015 *)
PROG
(PARI)
a(n) = {
my(x = bitand(n, n>>1), wt = k->hammingweight(k));
n - wt(n) + wt(x) - wt(bitand(x, n>>2));
};
vector(78, i, a(i-1)) \\ Gheorghe Coserea, Sep 24 2015
CROSSREFS
KEYWORD
nonn,base
AUTHOR
N. J. A. Sloane, Apr 07 2014
STATUS
approved