A154799 Records in A154804.

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

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