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 A130007 Products of two reversible primes that are the reverse of each other such that the products are also the sum of three consecutive primes. 1
 49, 121, 1207, 22801, 36481, 117907, 863041, 11986939, 32021347, 83148061, 88245211, 106110601, 217297081, 238733401, 242587711, 461772733, 487538353, 606191323, 683819293, 700500007, 758794243, 966634069, 989479087, 995821039, 1117186159, 1205213749, 1208515279 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Chai Wah Wu, Table of n, a(n) for n = 1..10000 EXAMPLE 121 = 11 * 11 = 37 + 41 +43 1207 = 17 * 71 = 397 + 401 + 409 117907 = 157 * 751 = 39293 + 39301 + 39313 MATHEMATICA PrevPrim[n_] := Block[{k = n - 1}, While[ !PrimeQ[k], k-- ]; k]; NextPrim[n_] := Block[{k = n + 1}, While[ !PrimeQ[k], k++ ]; k]; pal[n_] := FromDigits@ Reverse@ IntegerDigits@n; fQ[n_] := Block[{pn = pal@n, p, q, r, s}, q = PrevPrim[ Ceiling[n*pn/3]]; p = PrevPrim@q; r = NextPrim[ Floor[n*pn/3]]; s = NextPrim@r; n*pn == p + q + r || n*pn == q + r + s]; pd = 6; lst = {}; Do[ pd = NextPrim@pd; If[ PrimeQ@pd && fQ@pd, Print[pd*pal@pd]; AppendTo[lst, pd*pal@pd]], {n, 1000}]; lst = Union@lst - Robert G. Wilson v, Jun 19 2007 CROSSREFS Cf. A007500. Sequence in context: A115557 A167718 A080665 * A202331 A287005 A044300 Adjacent sequences:  A130004 A130005 A130006 * A130008 A130009 A130010 KEYWORD base,nonn AUTHOR Paolo P. Lava and Giorgio Balzarotti, Jun 15 2007 EXTENSIONS Corrected and extended by Robert G. Wilson v, Jun 19 2007 Corrected and extended and definition clarified by Chai Wah Wu, Feb 25 2018 STATUS approved

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Last modified September 17 16:57 EDT 2019. Contains 327136 sequences. (Running on oeis4.)