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A138839 Concatenation of initial and final digits of n-th perfect number, divided by 2. 0
33, 14, 23, 44, 18, 43, 9, 14, 13, 8, 9, 9, 13, 9, 29, 9, 48, 18, 8, 24, 8, 28, 18, 48, 8, 43, 18, 9, 9, 8, 14, 9, 43, 44, 18, 8, 43, 48, 23 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Also, concatenation of A135617(n) and A094540(n), divided by 2.

LINKS

Table of n, a(n) for n=1..39.

EXAMPLE

a(5)=18 because the 5th perfect number A000396(5) is 33550336 and the concatenation of initial and final digits of 33550336 is 36 and 36/2 = 18.

CROSSREFS

Cf. A000396, A073729, A135617, A094540, A138843.

Sequence in context: A123173 A147021 A200897 * A033353 A192631 A104781

Adjacent sequences:  A138836 A138837 A138838 * A138840 A138841 A138842

KEYWORD

base,easy,nonn

AUTHOR

Omar E. Pol, Apr 02 2008

STATUS

approved

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Last modified January 15 13:34 EST 2021. Contains 340187 sequences. (Running on oeis4.)