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A342615 a(0) = 0, a(1) = 1; a(2*n) = 9*a(n), a(2*n+1) = a(n) + a(n+1). 4
0, 1, 9, 10, 81, 19, 90, 91, 729, 100, 171, 109, 810, 181, 819, 820, 6561, 829, 900, 271, 1539, 280, 981, 919, 7290, 991, 1629, 1000, 7371, 1639, 7380, 7381, 59049, 7390, 7461, 1729, 8100, 1171, 2439, 1810, 13851, 1819, 2520, 1261, 8829, 1900, 8271, 8209, 65610, 8281, 8919, 2620 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..51.

FORMULA

G.f.: x * Product_{k>=0} (1 + 9*x^(2^k) + x^(2^(k+1))).

MATHEMATICA

a[0] = 0; a[1] = 1; a[n_] := If[EvenQ[n], 9 a[n/2], a[(n - 1)/2] + a[(n + 1)/2]]; Table[a[n], {n, 0, 51}]

nmax = 51; CoefficientList[Series[x Product[(1 + 9 x^(2^k) + x^(2^(k + 1))), {k, 0, Floor[Log[2, nmax]] + 1}], {x, 0, nmax}], x]

CROSSREFS

Cf. A002487, A178569, A178590, A237711, A244643, A342610, A342611, A342614.

Sequence in context: A135332 A098325 A101242 * A033046 A025635 A116555

Adjacent sequences:  A342612 A342613 A342614 * A342616 A342617 A342618

KEYWORD

nonn

AUTHOR

Ilya Gutkovskiy, Mar 16 2021

STATUS

approved

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Last modified August 1 07:45 EDT 2021. Contains 346384 sequences. (Running on oeis4.)