login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A330748 Index of the smallest element in A002182 that has exactly n prime factors counted with multiplicity. 4
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: A293033 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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 13 04:23 EDT 2021. Contains 344980 sequences. (Running on oeis4.)