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.

A320688 Sum of the square excess A056892 of the primes between two squares.

Original entry on oeis.org

3, 4, 6, 11, 10, 24, 26, 34, 26, 33, 50, 67, 72, 46, 70, 109, 96, 132, 122, 153, 132, 145, 174, 229, 208, 175, 194, 287, 232, 244, 338, 267, 276, 345, 374, 239, 392, 396, 424, 390, 484, 373, 514, 563, 618, 424, 654, 821, 442, 557, 890, 814, 668, 741, 580, 642, 990, 811, 982, 968, 772
Offset: 1

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Author

M. F. Hasler, Oct 19 2018

Keywords

Comments

Consider the primes p1,...,pK between two squares n^2 and (n+1)^2, and take the sum of the differences: (p1 - n^2) + ... + (pK - n^2). Obviously this equals (sum of these primes) - (number of these primes) * n^2.

Crossrefs

Row sums of A056892, read as a table.

Programs

  • Maple
    R:= NULL: p:= 2: n:= 1: t:= 0:
    while n <= 100 do
        t:= t + p-n^2;
        p:= nextprime(p);
        if p > (n+1)^2 then
         R:= R, t; t:= 0; n:= n+1;
        fi:
    od:
    R; # Robert Israel, Dec 17 2024
  • PARI
    a(n,s=0)={forprime(p=n^2,(n+1)^2,s+=p-n^2);s}

Formula

a(n) = A108314(n) - A014085(n)*A000290(n), where A000290(n) = n^2.