A138839 Concatenation of initial and final digits of n-th perfect number, divided by 2.

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

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