login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A154799 Records in A154804. 1
0, 1, 2, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, 19, 20, 21, 24, 28, 31, 33, 41, 42, 44, 52, 58, 69, 73, 76, 83, 92, 98, 115, 129, 138, 139, 154, 164, 165, 166, 172, 190, 198, 218, 223, 241, 268, 274, 292, 304, 330 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..52.

MAPLE

read("transforms") ; A008578 := proc(n) RETURN( n=1 or isprime(n) ) ; end : A154804 := proc(n) local a, d; a := 0 ; for d from 1 to n-1 do if A008578(n-d) and A008578(n+d) then a := a+1; fi; od: a ; end: a804 := [seq(A154804(n), n=1..5000)] ; r := RECORDS(a804)[1] ; # R. J. Mathar, Mar 14 2009

CROSSREFS

Cf. A008578, A154804, A154720, A154721.

Sequence in context: A031993 A023750 A091249 * A020660 A047306 A332108

Adjacent sequences:  A154796 A154797 A154798 * A154800 A154801 A154802

KEYWORD

more,nonn

AUTHOR

Omar E. Pol, Feb 01 2009

EXTENSIONS

More terms from R. J. Mathar, Mar 14 2009

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 21 12:16 EDT 2021. Contains 343150 sequences. (Running on oeis4.)