A330748 - OEIS

A330748

Index of the smallest element in A002182 that has exactly n prime factors counted with multiplicity.

1, 2, 3, 5, 6, 8, 12, 14, 19, 21, 23, 32, 37, 47, 50, 62, 70, 80, 91, 99, 105, 109, 124, 140, 143, 159, 166, 182, 198, 217, 221, 240, 253, 276, 297, 304, 327, 352, 357, 381, 398, 424, 449, 475, 485, 512, 540, 570, 584, 617, 642, 676, 704, 738, 765, 770, 805, 841, 877, 913, 937, 949, 985, 1021, 1058, 1096, 1134, 1169

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,2

LINKS

Michael De Vlieger, Table of n, a(n) for n = 0..4257 (computed using A. Flammenkamp's 779674-term HCN dataset; terms 0..329 from Antti Karttunen)

FORMULA

a(n) = min{k: A112778(k)=n}.

A002182(a(n)) = A328521(n).

A329902(a(n)) = A330743(n).

PROG

(PARI) A330748(n) = { for(k=1, #v112778, if(v112778[k]==n, return(k))); -(1/0); };

(PARI)

v329902 = readvec("a329902.txt"); \\ File for the first 779674 terms of A329902

A056239(n) = if(1==n, 0, my(f=factor(n)); sum(i=1, #f~, f[i, 2] * primepi(f[i, 1])));

A330748list() = { my(m=Map(), lista=List([]), t); for(i=1, #v329902, t = A056239(v329902[i]); if(!mapisdefined(m, t), mapput(m, t, i))); for(n=0, oo, if(mapisdefined(m, n, &t), listput(lista, t), return(Vec(lista)))); };

v330748 = A330748list();

A330748(n) = v330748[1+n];

for(n=0, #v330748-1, write("b330748.txt", n, " ", A330748(n))); \\ Antti Karttunen, Jan 13 2020

CROSSREFS

Cf. A001222, A002182, A112778, A328521, A329902, A330743.

Sequence in context: A370708 A002384 A096176 * A002243 A094763 A338916

Adjacent sequences: A330745 A330746 A330747 * A330749 A330750 A330751

KEYWORD

nonn

AUTHOR

Antti Karttunen, suggested by M. F. Hasler, Jan 10 2020

STATUS

approved