A074175 Duplicate of A074174.
44, 18, 172, 171, 45, 12, 45, 12, 236, 18, 52, 63, 50, 261, 524, 12, 28, 45, 44, 637, 404
Offset: 1
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.
44 is a member as 44 = 2^2*11 and 45 = 3^2*5.
filter:= proc(n) local F; F:= map(t -> t[2],ifactors(n)[2]); F = [2,1] or F = [1,2] end proc: A054753:= select(filter, {$1..10000}): sort(convert(A054753 intersect map(`-`,A054753,1),list)); # Robert Israel, Dec 06 2018
lst={}; Do[f1=FactorInteger[n]; If[Sort[Transpose[f1][[2]]]=={1, 2}, f2=FactorInteger[n+1]; If[Sort[Transpose[f2][[2]]]=={1, 2}, AppendTo[lst, n]]], {n, 3, 10000}]; lst
isok1(n) = vecsort(factor(n)[,2]) == [1,2]~; isok(n) = isok1(n) && isok1(n+1); \\ Michel Marcus, Sep 20 2017
18 is a member as 18 = 3^2*2 and 20 = 2^2*5.
lst={}; Do[f1=FactorInteger[n]; If[Sort[Transpose[f1][[2]]]=={1, 2}, f2=FactorInteger[n+2]; If[Sort[Transpose[f2][[2]]]=={1, 2}, AppendTo[lst, n]]], {n, 3, 10000}]; lst
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