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A088698
Replace 1 with 11 in binary representation of n.
7
0, 3, 6, 15, 12, 27, 30, 63, 24, 51, 54, 111, 60, 123, 126, 255, 48, 99, 102, 207, 108, 219, 222, 447, 120, 243, 246, 495, 252, 507, 510, 1023, 96, 195, 198, 399, 204, 411, 414, 831, 216, 435, 438, 879, 444, 891, 894, 1791, 240, 483, 486, 975, 492, 987, 990
OFFSET
0,2
LINKS
FORMULA
a(0)=0, a(2n) = 2a(n), a(2n+1) = 4a(n) + 3.
EXAMPLE
n=9: 1001 -> 110011 = 51, so a(9) = 51.
PROG
(PARI) a(n)=if(n<1, 0, if(n%2==0, 2*a(n/2), 4*a((n-1)/2)+3))
(Python)
def a(n): return int(bin(n)[2:].replace('1', '11'), 2)
print([a(n) for n in range(55)]) # Michael S. Branicky, Feb 20 2021
CROSSREFS
Ordered terms plus one are in A048297.
Same sequence sorted into ascending order: A277335, A290258 (without 0).
Main diagonal of A341520, right edge of A341521.
Sequence in context: A162276 A261955 A144615 * A105802 A285844 A285948
KEYWORD
nonn,easy,base
AUTHOR
Ralf Stephan, Oct 07 2003
STATUS
approved