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Revision History for A134712

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A134712

Base-2 logarithm of (n-th even superperfect number divided by 2^n).
(history; published version)

#6 by Wesley Ivan Hurt at Wed Apr 14 00:04:44 EDT 2021

STATUS

proposed

approved

#5 by Jon E. Schoenfield at Wed Apr 14 00:00:11 EDT 2021

STATUS

editing

proposed

#4 by Jon E. Schoenfield at Wed Apr 14 00:00:09 EDT 2021

NAME

Base -2 logarithm of (n-th even superperfect number divided by 2^n).

FORMULA

a(n) =base log_2 logarithm of (A061652(n)/(2^n)) = A000043(n) - n - 1 = A090748(n) - n.

EXAMPLE

a(5)=7 because the 5th even superperfect number is 4096, 2^5=32, 4096/32=128 and base log_2 logarithm of (128 is ) = 7 (because 2^7=128).

STATUS

approved

editing

#3 by Charles R Greathouse IV at Tue Mar 11 01:34:10 EDT 2014

LINKS

O. Omar E. Pol, <a href="http://www.polprimos.com">Determinacion geometrica de los numeros primos y perfectos</a>.

Discussion

Tue Mar 11

01:34

OEIS Server: https://oeis.org/edit/global/2123

#2 by Russ Cox at Fri Mar 30 17:33:50 EDT 2012

AUTHOR

_Omar E. Pol (info(AT)polprimos.com), _, Nov 07 2007

Discussion

Fri Mar 30

17:33

OEIS Server: https://oeis.org/edit/global/157

#1 by N. J. A. Sloane at Sat Nov 10 03:00:00 EST 2007

NAME

Base 2 logarithm of (n-th even superperfect number divided by 2^n).

DATA

0, 0, 1, 2, 7, 10, 11, 22, 51, 78, 95, 114, 507, 592, 1263, 2186, 2263, 3198, 4233, 4402, 9667, 9918, 11189, 19912, 21675, 23182, 44469, 86214, 110473, 132018, 216059, 756806, 859399, 1257752, 1398233, 2976184, 3021339, 6972554, 13466877

OFFSET

1,4

LINKS

O. E. Pol, <a href="http://www.polprimos.com">Determinacion geometrica de los numeros primos y perfectos</a>.

FORMULA

a(n)=base 2 logarithm of (A061652(n)/(2^n)) = A000043(n)-n-1 = A090748(n)-n.

EXAMPLE

a(5)=7 because the 5th even superperfect number is 4096, 2^5=32, 4096/32=128 and base 2 logarithm of 128 is 7 (because 2^7=128).

CROSSREFS

Cf. A000043, A000396, A000668, A019279, A061652, A090748, A133028.

KEYWORD

nonn,new

AUTHOR

Omar E. Pol (info(AT)polprimos.com), Nov 07 2007

STATUS

approved