A134837 Composite numbers where the sum of the smallest prime factor and the largest prime factor is an odd composite.

14, 26, 28, 38, 42, 46, 52, 56, 62, 70, 74, 76, 78, 84, 86, 92, 94, 98, 104, 106, 112, 114, 122, 124, 126, 130, 134, 138, 140, 146, 148, 152, 156, 158, 166, 168, 172, 178, 182, 184, 186, 188, 190, 194, 196, 206, 208, 210, 212, 218, 222, 224, 226, 228, 230, 234

Offset

1,1

Links

Table of n, a(n) for n=1..56.

Example

14 is in the sequence as 14=2*7 and 2+7=9, an odd composite; 60 is not, as 60=2^2*3*5 and 2+5 is 7, not composite.

Mathematica

Select[Range[240], CompositeQ[#] && CompositeQ[c = Min[First/@FactorInteger[#]] + Max[First/@FactorInteger[#]]] && OddQ[c] &] (* Stefano Spezia, Aug 02 2024 *)

Crossrefs

Cf. A002808.

Sequence in context: A256573 A030786 A094163 * A105583 A323030 A005277

Adjacent sequences: A134834 A134835 A134836 * A134838 A134839 A134840

Keyword

nonn

Author

Juri-Stepan Gerasimov, Jan 04 2009

Extensions

Definition and examples simplified by D. S. McNeil, Dec 10 2009

Corrected and extended by D. S. McNeil, Dec 10 2009

Status

approved