A026100 a(n) = number of the column of A026098 that contains n.

1, 2, 1, 3, 1, 2, 1, 4, 3, 2, 1, 4, 1, 2, 3, 5, 1, 5, 1, 4, 3, 2, 1, 6, 5, 2, 6, 4, 1, 7, 1, 8, 3, 2, 5, 7, 1, 2, 3, 6, 1, 6, 1, 4, 7, 9, 1, 8, 7, 8, 3, 4, 1, 9, 5, 10, 3, 2, 1, 9, 1, 11, 8, 12, 5, 6, 1, 4, 2, 9, 1, 10, 1, 2, 10, 4, 7, 6, 1, 11, 11, 13, 1, 10, 5, 14, 3, 8, 1, 12, 7, 3, 2, 15, 5, 13, 1, 11, 9, 12

Offset

1,2

Links

Antti Karttunen, Table of n, a(n) for n = 1..19477

Prog

(PARI)
getrow(n, all) = {if (n==1, return ([1])); if (n==2, return ([3, 2])); my(row = vector(n)); row[1] = prime(n); for (k=2, n, my(ok = 0, m = 1, val); until(ok, val = m*prime(n+1-k); if (!setsearch(all, val) && !setsearch(Set(row), val), ok = 1); m++; ); row[k] = val; ); return (row); };
A026100list(up_to_row) = { my(all = [], m = Map(), lista = List([]), u); for(n=1, up_to_row, my(row = getrow(n, all)); for(k=1, n, mapput(m, row[k], k)); all = Set(concat(all, row))); for(n=1, oo, if(mapisdefined(m, n, &u), listput(lista, u), if(isprime(n)&&(n>2), listput(lista, 1), return(Vec(lista))))); };
v026100 = A026100list(1200);
A026100(n) = v026100[n]; \\ Antti Karttunen, Jan 18 2020, after program in A026098 provided by Michel Marcus.

Crossrefs

Cf. A026098.

Sequence in context: A277892 A214743 A331179 * A059127 A319494 A105609

Adjacent sequences: A026097 A026098 A026099 * A026101 A026102 A026103

Keyword

nonn,look

Author

Clark Kimberling

Extensions

a(27) onward corrected by Sean A. Irvine, Sep 15 2019

Status

approved