

A332788


Positivepan primes (see Comments).


2



5, 31, 59, 107, 271, 223, 269, 313, 647, 457, 503, 941, 1579, 12919, 3571, 1667, 2897, 3037, 3187, 1993, 3461, 2179, 10141, 5927, 11969, 4957, 13627, 5519, 22787, 3851, 3889, 3929, 15217, 44221, 65867, 21799, 10211, 31727, 24623, 11467
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


COMMENTS

Take a doublepan balance scale and name the pans "negative" and "positive". At each step, the question is: "Is there an unused prime that would balance the scale if added to the positive pan? If the answer is yes, add that prime to the positive pan. Otherwise, add the smallest unused prime to the negative pan.
Is the number of primes in the positive pan (P) infinite? If it is, is fractalization of P, i.e., further subdivision into PN and PP subpans, possible (including infinitely)?


LINKS

Table of n, a(n) for n=1..40.


EXAMPLE

2 and 3 unbalance the scale (and go to the negative pan N), but 5 = 2 + 3 balances it (and goes to the positive pan P).


MATHEMATICA

a[1]=2; a[n_]:=a[n]=Module[{tab=Table[a[i], {i, 1, n1}],
totalN=Abs[Total[Select[Table[a[i], {i, 1, n1}], Negative]]],
totalP=Total[Select[Table[a[i], {i, 1, n1}], Positive]],
l=NextPrime[Last[Select[Table[a[i], {i, 1, n1}], Negative]], 1],
m=NextPrime[Abs[Last[Select[Table[a[i], {i, 1, n1}], Negative]]]]},
If[totalN==totalP,
If[PrimePi[tab[[1]]]PrimePi[Abs[tab[[2]]]]==1, NextPrime[tab[[1]]],
If[FreeQ[Abs[tab], m], m, While[! FreeQ[Abs[tab], m], m=NextPrime[m]]; m]],
If[PrimeQ[totalNtotalP]&&FreeQ[Abs[tab], totalNtotalP], totalNtotalP,
If[FreeQ[Abs[tab], Abs[l]], l, While[!FreeQ[Abs[tab], Abs[l]], l=NextPrime[l, 1]]; l]
]]]; Select[a/@Range[370], Positive]


CROSSREFS

Cf. A075326, A332341, A332787.
Sequence in context: A245523 A147033 A125743 * A333243 A078686 A031908
Adjacent sequences: A332785 A332786 A332787 * A332789 A332790 A332791


KEYWORD

nonn


AUTHOR

Ivan N. Ianakiev, Feb 24 2020


STATUS

approved



