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A072800 Composition of A030101 and A014486. Binary encodings of parenthesizations, Dyck paths and other Catalan structures reversed. 2
0, 1, 5, 3, 21, 13, 19, 11, 7, 85, 53, 77, 45, 29, 83, 51, 75, 43, 27, 71, 39, 23, 15, 341, 213, 309, 181, 117, 333, 205, 301, 173, 109, 285, 157, 93, 61, 339, 211, 307, 179, 115, 331, 203, 299, 171, 107, 283, 155, 91, 59, 327, 199, 295, 167, 103, 279, 151, 87, 55 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
COMMENTS
See A014486.
LINKS
Dana G. Korssjoen, Biyao Li, Stefan Steinerberger, Raghavendra Tripathi, and Ruimin Zhang, Finding structure in sequences of real numbers via graph theory: a problem list, arXiv:2012.04625 [math.CO], 2020-2021. See numerators of fractions in Section 2.8. (For denominators see A339570.)
FORMULA
a(n) = A030101(A014486(n)).
PROG
(PARI)
isA014486(n) = { my(v=binary(n), t=0); for(i=1, #v, t+=if(v[i], 1, -1); if(t<0, return(0))); t==0; }; \\ From A014486
A030101(n) = if(n<1, 0, subst(Polrev(binary(n)), x, 2));
k=0; n=0; while(k<23714, if(isA014486(n), write("b072800.txt", k, " ", A030101(n)); k++); n++); \\ Antti Karttunen, Mar 28 2022
CROSSREFS
Cf. A014486, A030101, A339570 (gives the denominators).
Sequence in context: A171621 A084183 A099730 * A199637 A199636 A324038
KEYWORD
nonn,frac,base,look
AUTHOR
Antti Karttunen, Jun 12 2002
STATUS
approved

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Last modified March 28 07:48 EDT 2024. Contains 371235 sequences. (Running on oeis4.)