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.
109 is in the list because it is the prime A000040(29) and can be written as 74+35=R(47)+R(53)= A004087(15)+A004087(16).
109 is in the list because it is the sum of R(47)+R(53)=74+35=109.
Take[Union[Total[IntegerReverse[#]]&/@Partition[Prime[Range[500]],2,1]],100] (* The program is not suitable for more than 100 or so terms. *) (* Harvey P. Dale, Apr 26 2022 *)
14 = R(7) + R(7) = R(3) + R(11). 28 = R(11) + R(71) = 11 + 17 = R(41) + R(41) = 14 + 14. 33 = 2 + 31 = R(2) + R(13) = 16 + 17 = R(61) + R(71). 36 = R(2) + R(43) = 2 + 34 = R(5) + R(13) = 5 + 31.
read("transforms") ; A055642 := proc(n) max(1, ilog10(n)+1) ; end:
A004087 := proc(n) option remember; digrev(ithprime(n)) ; end:
isA162708 := proc(n) c := 0 ; for i from 1 do p := ithprime(i) ; if A055642(p) > A055642(n) then break; fi; for j from 1 to i do if A004087(i)+A004087(j) = n then c := c+1; fi; od: od: RETURN(c > 1); end:
for n from 1 to 200 do if isA162708(n) then printf("%d,",n) ; fi; od: # R. J. Mathar, Jul 13 2009
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