1,2

G. E. Andrews, MacMahon's prime numbers of measurement, Amer. Math. Monthly, 82 (1975), 922-923.

R. K. Guy, Unsolved Problems in Number Theory, E30.

P. A. MacMahon, The prime numbers of measurement on a scale, Proc. Camb. Phil. Soc. 21 (1923), 651-654; reprinted in Coll. Papers I, pp. 797-800.

Problem E1910, Amer. Math. Monthly, 75 (1968), 80-81.

R. J. Mathar, Table of n, a(n) for n = 1..7836

Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.

(Maple program from R. J. Mathar, Jun 04 2006) A002048 := proc(anmax::integer, printlist::boolean)

local a, asum, su, i, piv, j;

a := [];

for i from 1 to anmax do

a := [op(a), i];

od:

if printlist then

printf("%d %d\n", 1, a[1]);

printf("%d %d\n", 2, a[2]);

fi;

asum := [a[1]+a[2], a[2]];

for i from 3 to anmax do

asum := [op(asum), 0];

od:

piv := 3;

while piv <= nops(a) do

for i from 1 to piv-2 do

a := remove(has, a, asum[i]);

od:

if printlist then

printf("%a %a\n", piv, a[piv]);

fi;

for i from 1 to piv do

asum := subsop(i=asum[i]+a[piv], asum);

od:

piv := piv+1;

od;

RETURN(a);

end:

A002048(40000, true);

(C++) #include <iostream> #include <vector> #include <algorithm> #define NMAX 400 using namespace std; int main(int argc, char *argv[]) { vector<int> a; for(int i=0; i< NMAX; i++) a.push_back(i+1); for(int piv=2; piv < a.size(); piv++) for(int i=0; i < piv-1 && i < a.size()-1; i++) { int su= a[i]+a[i+1]; remove(a.begin(), a.end(), su); for(int j=i+2; j < piv && j < a.size(); j++) { su += a[j]; remove(a.begin(), a.end(), su); if(su > NMAX) break; } } for(int i=0; i < a.size() && a[i] < NMAX; i++) cout << a[i] << ", "; return 0; } - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 31 2006

Cf. A002049.

Sequence in context: A057129 A036404 A018498 this_sequence A067941 A092265 A101274

Adjacent sequences: A002045 A002046 A002047 this_sequence A002049 A002050 A002051

nonn,nice

njas

More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 31 2006