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A256179 Sequence of power towers in ascending order, using all possible permutations of 2s and 3s. 5
2, 3, 4, 8, 9, 16, 27, 81, 256, 512, 6561, 19683, 65536, 43046721, 134217728, 7625597484987, 2417851639229258349412352, 443426488243037769948249630619149892803, 115792089237316195423570985008687907853269984665640564039457584007913129639936 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(n) is found by treating the digits of A248907(n) as power towers, so the sequence starts 2, 3, 2^2=4, 2^3=8, 3^2=9, 2^(2^2)=16, 3^3=27, 3^(2^2)=81, 2^(2^3)=256...

LINKS

Table of n, a(n) for n=1..19.

Vladimir Reshetnikov, 2-3 sequence puzzle, SeqFan list, Mar 18 2015.

FORMULA

A256179 = A256229 o A248907 = A256229 o A032810 o A185969, i.e., a(n) = A256229(A248907(n)) = A256229(A032810(A185969(n))).

Recurrence: a(1)=2, a(2)=3, a(3)=2^2, a(4)=2^3, a(5)=3^2, a(6)=2^(2^2), a(7)=3^3, a(8)=3^(2^2), a(9)=2^(2^3), a(10)=2^(3^2), a(11)=3^(2^3), a(12)=3^(3^2); and for n>6, a(2n)=3^a(n-1), a(2n-1)=2^a(n-1). - Vladimir Reshetnikov, Mar 19 2015

EXAMPLE

a(12) = 19683 because A248907(12) = 332, and 3^(3^2) = 19683.

PROG

(PARI) A256179(n)=A256229(A248907[n])) \\ where A248907 is assumed to be defined as vector. - M. F. Hasler, Mar 19 2015

CROSSREFS

Cf. A185969, A248907, A075877.

Sequence in context: A074311 A076382 A006899 * A078830 A304521 A026489

Adjacent sequences:  A256176 A256177 A256178 * A256180 A256181 A256182

KEYWORD

nonn

AUTHOR

Bob Selcoe, Mar 18 2015

EXTENSIONS

More terms from M. F. Hasler, Mar 19 2015

STATUS

approved

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Last modified October 13 20:38 EDT 2019. Contains 327981 sequences. (Running on oeis4.)