login
A342923
Numbers k such that A342925(k) = k + 3*A003415(k).
11
120, 672, 963, 1036, 264768, 523776, 459818240, 1476304896
OFFSET
1,1
COMMENTS
2^33 < a(9) <= A005820(6) = 51001180160.
MATHEMATICA
Select[Range[6*10^5], #3 == #1 + 3 #2 & @@ Prepend[Map[If[# < 2, 0, # Total[#2/#1 & @@@ FactorInteger[#]]] &, {#, DivisorSigma[1, #]}], #] &] (* Michael De Vlieger, Feb 25 2022 *)
PROG
(PARI)
A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
A342925(n) = A003415(sigma(n));
isA342923(n) = (A342925(n)==(n+(3*A003415(n))));
CROSSREFS
Cf. A005820 (subsequence).
Sequence in context: A235768 A179963 A229568 * A292365 A306373 A356548
KEYWORD
nonn,more
AUTHOR
Antti Karttunen, Apr 08 2021
EXTENSIONS
a(8) from Antti Karttunen, Feb 25 2022
STATUS
approved