login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

(0, 1, 2, 3, 2^2, 5, 2*3, 7, 2^3, 3^2, 2*5, 11, 2^2*3, ...) transform in (0*1, 2*3, 2*2, 5*2, 3*7, 2*3, 3*2, 2*5, 11*2, 2*3, ...).
15

%I #22 Jan 25 2023 09:24:03

%S 0,6,4,10,21,6,6,10,22,6,26,21,10,68,6,38,4,15,14,253,6,15,4,39,6,14,

%T 58,15,62,15,22,85,14,6,74,38,39,6,205,6,301,4,33,10,46,94,12,14,10,6,

%U 34,26,106,9,55,6,21,38,1711,4,15,122,93,14,12,65,6,737,4,51,46,35,142,9

%N (0, 1, 2, 3, 2^2, 5, 2*3, 7, 2^3, 3^2, 2*5, 11, 2^2*3, ...) transform in (0*1, 2*3, 2*2, 5*2, 3*7, 2*3, 3*2, 2*5, 11*2, 2*3, ...).

%H Seiichi Manyama, <a href="/A141270/b141270.txt">Table of n, a(n) for n = 1..10000</a>

%t Map[Times @@ # &, Partition[Flatten[{0}~Join~Array[DeleteCases[Flatten@ FactorInteger[#], 1] &, 72] /. {} -> {1}], 2, 2]] (* _Michael De Vlieger_, Oct 20 2021 *)

%Y Cf. A136734, A141269.

%K nonn,less

%O 1,2

%A _Juri-Stepan Gerasimov_, Aug 08 2008

%E A 65 replaced with 85, a 54 with 74, etc. by _R. J. Mathar_, Feb 21 2009