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 A048715 Binary expansion matches (100(0)*)*; or, Zeckendorf-like expansion of n using recurrence f(n) = f(n-1) + f(n-3). 12
 0, 1, 2, 4, 8, 9, 16, 17, 18, 32, 33, 34, 36, 64, 65, 66, 68, 72, 73, 128, 129, 130, 132, 136, 137, 144, 145, 146, 256, 257, 258, 260, 264, 265, 272, 273, 274, 288, 289, 290, 292, 512, 513, 514, 516, 520, 521, 528, 529, 530, 544, 545, 546, 548, 576, 577, 578, 580 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS No more than one 1-bit in each bit triple. All terms satisfy A048727(n) = 7*n. Constructed from A000930 in the same way as A003714 is constructed from A000045. It appears that n is in the sequence if and only if C(7n,n) is odd (cf. A003714). - Benoit Cloitre, Mar 09 2003 The conjecture by Benoit is correct. This is easily proved using the well-known result that the multiplicity with which a prime p divides C(n+m,n) is the number of carries when adding n+m in base p. - Franklin T. Adams-Watters, Oct 06 2009 LINKS G. C. Greubel, Table of n, a(n) for n = 0..1275 FORMULA a(0) = 0, a(n) = (2^(invfoo(n)-1))+a(n-foo(invfoo(n))), where foo(n) is foo(n-1) + foo(n-3) (A000930) and invfoo is its "integral" (floored down) inverse. a(n) XOR 6*a(n) = 7*a(n); 3*a(n) XOR 4*a(n) = 7*a(n); 3*a(n) XOR 5*a(n) = 6*a(n); (conjectures). - Paul D. Hanna, Jan 22 2006 MATHEMATICA Reap[Do[If[OddQ[Binomial[7n, n]], Sow[n]], {n, 0, 400}]][[2, 1]] PROG (PARI) is(n)=!bitand(n, 6*n) \\ Charles R Greathouse IV, Oct 03 2016 CROSSREFS Subsequence of A048716. Cf. A048717-A048719, A004742-A004744, A003726, A048730, A048733, A115422-A115424. Sequence in context: A182653 A036349 A155562 * A242662 A028982 A320137 Adjacent sequences:  A048712 A048713 A048714 * A048716 A048717 A048718 KEYWORD nonn,easy AUTHOR Antti Karttunen, Mar 30 1999 STATUS approved

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Last modified October 18 02:23 EDT 2019. Contains 328135 sequences. (Running on oeis4.)