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.

A024448 a(n) = 3rd elementary symmetric function of the first n+2 primes.

Original entry on oeis.org

30, 247, 1358, 5102, 16186, 41817, 98190, 220628, 441410, 852887, 1551568, 2631642, 4293186, 6866813, 10757450, 16151192, 23873746, 34440605, 48249066, 66877582, 91117898, 122953643, 165196270, 218615372, 284119458, 364962773, 462059210, 579605426, 732954370
Offset: 1

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Programs

  • Maple
    SymmPolyn := proc(L::list,n::integer)
        local c,a,sel;
        a :=0 ;
        sel := combinat[choose](nops(L),n) ;
        for c in sel do
            a := a+mul(L[e],e=c) ;
        end do:
        a;
    end proc:
    A024448 := proc(n)
        [seq(ithprime(k),k=1..n+2)] ;
        SymmPolyn(%,3) ;
    end proc: # R. J. Mathar, Sep 23 2016
    # second Maple program:
    b:= proc(n) option remember; convert(series(`if`(n=0, 1,
          b(n-1)*(ithprime(n)*x+1)), x, 4), polynom)
        end:
    a:= n-> coeff(b(n+2), x, 3):
    seq(a(n), n=1..30);  # Alois P. Heinz, Sep 06 2019
  • Mathematica
    b[n_] := b[n] = If[n == 0, 1, b[n - 1] (Prime[n] x + 1)];
    a[n_] := SeriesCoefficient[b[n + 2], {x, 0, 3}];
    a /@ Range[30] (* Jean-François Alcover, Feb 03 2020, after Alois P. Heinz *)