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Search: id:A133968
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| A133968 |
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Home primes whose homeliness is 7. |
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+0
13
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| 23251, 23761, 33797, 36389, 37643, 37951, 37967, 77711, 113779, 131777, 132749, 134129, 233347, 233617, 233881, 237547, 293863, 311677, 311821, 313619, 314627, 317743, 319547, 331319, 331907, 333139, 333271, 333457, 333791, 333911, 337517
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Number of terms < 10^n: 0, 0, 0, 0, 8, 80, 667, ....
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MATHEMATICA
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lst = {}; f[n_] := FromDigits@ Flatten[ IntegerDigits@ Table[ #[[1]], {#[[2]]}] & /@ FactorInteger@n, 2]; h[n_] := NestWhileList[f@# &, n, !PrimeQ@# &, 1, 28]; Do[p = h[n][[ -1]]; If[ PrimeQ@p && p < 10^7 && p != n, Print[{n, p}]; AppendTo[lst, p]], {n, 2, 1000}];
d = 7 - 2; lsu = {}; Do[ If[ lst[[n]] == lst[[n + d]] && lst[[n - 1]] != lst[[n]] && lst[[n]] != lst[[n + d + 1]], AppendTo[lsu, lst[[n]]]], {n, 188004 - d - 1}]; Take[Union@ lsu, 35]
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CROSSREFS
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Cf. A037274, A118756, A133967, A133956, A000014, A133958, A133960, A133962, A133964, A133966, A133970, A133972, A133974, A133976, A133978.
Sequence in context: A087425 A075784 A126301 this_sequence A031847 A069334 A118061
Adjacent sequences: A133965 A133966 A133967 this_sequence A133969 A133970 A133971
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KEYWORD
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nonn
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), Sep 30 2007
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