login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A134705
a(n) = n-th perfect number divided by 2^n.
2
3, 7, 62, 508, 1048448, 134216704, 1073739776, 9007199250546688, 5192296858534827626278696515534848, 187072209578355573530071658285452771612302071824384
OFFSET
1,1
FORMULA
a(n)=A000396(n)/(2^n).
EXAMPLE
a(3)=62 because the 3rd perfect number is 496 and 2^3=8 and 496/8=62.
MAPLE
perfp := [1, 2, 4, 6, 12, 16, 18, 30, 60, 88, 106, 126, 520, 606, 1278, 2202, 2280, 3216, 4252] : A000396 := proc(n) global perfp ; 2^op(n, perfp)*(2^(op(n, perfp)+1)-1) ; end: A134705 := proc(n) A000396(n)/2^n ; end: seq(A134705(n), n=1..12) ; # R. J. Mathar
CROSSREFS
Sequence in context: A258184 A362347 A077703 * A110433 A219845 A041817
KEYWORD
nonn
AUTHOR
Omar E. Pol, Nov 07 2007
EXTENSIONS
More terms from R. J. Mathar, Jan 07 2008
STATUS
approved