A077201 Erroneous version of A120426.
1, 3, 5, 49, 11, 22, 17, 16983563041, 529, 38, 31
Offset: 0
This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
a(14) = 3 as 14 has prime signature [1, 1] and it's the third positive integer having that prime signature, after 6 and 10.
p:= proc() 0 end:
a:= proc(n) option remember; local t; a(n-1); t:=
(l-> mul(ithprime(i)^l[i][2], i=1..nops(l)
))(sort(ifactors(n)[2])); p(t):= p(t)+1
end: a(0):=0:
seq(a(n), n=1..100); # Alois P. Heinz, Jun 01 2020
A071364[n_] := If[n == 1, 1, With[{f = FactorInteger[n]}, Times @@ (Prime[Range[Length[f]]]^f[[All, 2]])]]; Module[{b}, b[_] = 0; a[n_] := With[{t = A071364[n]}, b[t] = b[t] + 1]]; Array[a, 105] (* Jean-François Alcover, Jan 10 2022 *)
first(n) = { my(m = Map(), res = vector(n)); for(i = 1, n, c = factor(i)[,2]; if(mapisdefined(m, c), res[i] = mapget(m, c) + 1; mapput(m, c, res[i]) , res[i] = 1; mapput(m, c, 1) ) ); res }