A072800 - OEIS

A072800

Composition of A030101 and A014486. Binary encodings of parenthesizations, Dyck paths and other Catalan structures reversed.

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

Antti Karttunen, Table of n, a(n) for n = 0..23713

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.)

Index entries for sequences related to binary expansion of n

Index entries for sequences related to parenthesizing

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

Adjacent sequences: A072797 A072798 A072799 * A072801 A072802 A072803

KEYWORD

nonn,frac,base,look

AUTHOR

Antti Karttunen, Jun 12 2002

STATUS

approved