cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A094931 A measure of the excess of the mean of the set of 4 consecutive primes over the 2nd of the set.

Original entry on oeis.org

5, 6, 8, 4, 8, 4, 12, 10, 4, 14, 4, 4, 12, 14, 8, 4, 14, 4, 6, 14, 8, 16, 14, 2, 4, 8, 4, 20, 28, 0, 10, 8, 20, 0, 16, 10, 8, 14, 8, 8, 20, 0, 8, 12, 34, 16, 0, 4, 12, 10, 8, 24, 8, 12, 8, 4, 14, 4, 10, 32, 22, 0, 4, 20, 30, 8, 16, 0, 12, 16, 16, 10, 10, 8, 16, 14, 8, 22, 14, 4, 20, 0, 14, 8
Offset: 4

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Author

Roger L. Bagula, Jun 17 2004

Keywords

Comments

Let (prime(n-3)+prime(n-2)+prime(n-1)+prime(n))/4 = A034963(n-3)/4 be the arithmetic mean of 4 consecutive primes, and prime(n-2) the third largest. Then A034963(n-3)-4*prime(n-2) is an integer measure of the excess of the mean. We define a(n) by the excess if positive, else by 0.

Crossrefs

Cf. A034963.

Programs

  • Maple
    A094931 := proc(n)
        local p3,p2,p1,p0 ;
        p3 := ithprime(n-3) ;
        p2 := ithprime(n-2) ;
        p1 := ithprime(n-1) ;
        p0 := ithprime(n) ;
        max(p3-3*p2+p1+p0,0) ;
    end proc:
    seq(A094931(n),n=4..50) ; # R. J. Mathar, Nov 15 2019
  • Mathematica
    a=Table[If[(Prime[n-3]+Prime[n-2]+Prime[n-1]+Prime[n])/4-Prime[n-2]>0, 4*((Prime[n-3]+Prime[n-2]+Prime[n-1]+Prime[n])/4-Prime[n-2]), 0], {n, 4, 204}]
    If[#<=0,0,#]&/@(4(Total[#]/4-#[[2]])&/@Partition[Prime[Range[90]],4,1]) (* Harvey P. Dale, Mar 02 2015 *)