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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A141607 Nonprimes of the form n-(p(n+1)-p(n-2))/(p(n)-p(n-1)), where p(n)=n-th prime. 0
 0, 1, 4, 6, 8, 9, 10, 12, 15, 20, 21, 22, 24, 25, 26, 27, 33, 35, 36, 44, 45, 48, 50, 51, 57, 60, 62, 63, 68, 69, 72, 74, 75, 82, 84, 85, 90, 93, 98, 105, 110, 111, 115, 121, 122, 126, 129, 134, 135, 136, 138, 142, 143, 144, 145, 147, 148, 158, 165, 166, 169, 170, 172, 174, 176 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Entries are not repeated and shown in natural order. LINKS EXAMPLE n=4: 4-(11-3)/(7-5)=0=a(1). n=6: 6-(17-7)/(13-11)=1=a(2). n=9: 9-(29-17)/(23-19)=6=a(4). n=10: 10-(31-19)/(29-23)=8=a(5). n=11: 11-(37-23)/(31-29)=4=a(3). MATHEMATICA Select[PrimePi[#[[3]]]-(#[[4]]-#[[1]])/(#[[3]]-#[[2]])&/@ Partition[ Prime[ Range[200]], 4, 1], IntegerQ[#]&&!PrimeQ[#]&]//Union (* Harvey P. Dale, Jul 06 2017 *) CROSSREFS Cf. A000040. Sequence in context: A306307 A248010 A067013 * A071070 A275722 A047820 Adjacent sequences:  A141604 A141605 A141606 * A141608 A141609 A141610 KEYWORD nonn AUTHOR Juri-Stepan Gerasimov, Sep 10 2008 EXTENSIONS Corrected and extended by R. J. Mathar, Sep 26 2008 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.

Last modified April 1 10:33 EDT 2020. Contains 333159 sequences. (Running on oeis4.)