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A162708 Numbers that are the sum of two reversed primes in more than one way. 0
10, 14, 16, 18, 19, 20, 21, 22, 24, 27, 28, 30, 33, 34, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 54, 66, 68, 69, 70, 72, 73, 74, 75, 76, 78, 79, 81, 82, 84, 85, 86, 87, 88, 89, 90, 92, 93, 94, 95, 96, 97, 98, 99, 100, 102, 103, 104, 105, 106, 107, 108, 109 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Subsequence of A162706. - R. J. Mathar, Jul 13 2009

LINKS

Table of n, a(n) for n=1..69.

EXAMPLE

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.

MAPLE

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

CROSSREFS

Sequence in context: A229271 A088711 A154774 * A330210 A067188 A092632

Adjacent sequences:  A162705 A162706 A162707 * A162709 A162710 A162711

KEYWORD

nonn,base

AUTHOR

Claudio Meller, Jul 11 2009

EXTENSIONS

Missing terms 14, 33, etc. inserted by R. J. Mathar, Jul 13 2009

STATUS

approved

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Last modified July 29 11:49 EDT 2021. Contains 346345 sequences. (Running on oeis4.)