The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A338908 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
Showing entries 1-10 | older changes

A338908

Squarefree semiprimes whose prime indices sum to an even number.
(history; published version)

#16 by Alois P. Heinz at Mon Feb 01 22:16:06 EST 2021

STATUS

proposed

approved

#15 by Jon E. Schoenfield at Mon Feb 01 22:12:48 EST 2021

STATUS

editing

proposed

#14 by Jon E. Schoenfield at Mon Feb 01 22:12:44 EST 2021

CROSSREFS

A338906 is the non-squarefree nonsquarefree version.

STATUS

approved

editing

#13 by Alois P. Heinz at Thu Dec 03 12:32:41 EST 2020

STATUS

proposed

approved

#12 by Gus Wiseman at Thu Dec 03 08:43:00 EST 2020

STATUS

editing

proposed

#11 by Gus Wiseman at Thu Dec 03 08:33:40 EST 2020

CROSSREFS

A339192 gives the sum of squarefree semiprimes of weight n.

STATUS

approved

editing

#10 by N. J. A. Sloane at Sun Nov 29 21:56:25 EST 2020

STATUS

proposed

approved

#9 by Gus Wiseman at Sun Nov 29 20:37:31 EST 2020

STATUS

editing

proposed

#8 by Gus Wiseman at Sun Nov 29 20:36:32 EST 2020

MATHEMATICA

Select[Range[100], SquareFreeQ[#]&&PrimeOmega[#]==2&& EvenQ[Total[PrimePi/@First/@FactorInteger[#]]]&]

STATUS

proposed

editing

Discussion

Sun Nov 29

20:37

Gus Wiseman: Long programs affect the width of the whole entry, so I inserted a space.

#7 by Gus Wiseman at Sun Nov 29 20:35:44 EST 2020

STATUS

editing

proposed