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A247363 Central terms of triangle A247358. 3
1, 3, 16, 64, 343, 4096, 59049, 1000000, 14348907, 129140163, 1475789056, 38443359375, 1099511627776, 34271896307633, 1156831381426176, 42052983462257059, 1152921504606846976, 18446744073709551616, 295147905179352825856, 12116574790945106558976 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

For all n there exist b(n) and e(n) such that: a(n)=b(n)^e(n) and b(n)+e(n)=2*n, see example.

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..400

FORMULA

a(n) = A247358(2*n-1,n).

EXAMPLE

.   n |        a(n) | b(n)^e(n) | b(n)+e(n)

. ----+-------------+-----------+----------

.   1 |           1 |    1^1    |     2

.   2 |           3 |    3^1    |     4

.   3 |          16 |    2^4    |     6

.   4 |          64 |    2^6    |     8

.   5 |         343 |    7^3    |    10

.   6 |        4096 |    8^4    |    12

.   7 |       59049 |    9^5    |    14

.   8 |     1000000 |   10^6    |    16

.   9 |    14348907 |    3^15   |    18

.  10 |   129140163 |    3^17   |    20

.  11 |  1475789056 |   14^8    |    22

.  12 | 38443359375 |   15^9    |    24

PROG

(Haskell)

a247363 n = a247358 (2 * n - 1) n

(Python)

def A247363(n):

....return(sorted((b+1)**((2*n-1)-b) for b in range(2*n-1))[n-1])

# Chai Wah Wu, Sep 14 2014

CROSSREFS

Cf. A247358, A000169.

Sequence in context: A155160 A267036 A037451 * A007143 A062960 A293579

Adjacent sequences:  A247360 A247361 A247362 * A247364 A247365 A247366

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Sep 14 2014

STATUS

approved

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Last modified October 20 12:34 EDT 2018. Contains 316379 sequences. (Running on oeis4.)