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Search: id:A133960
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| A133960 |
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Home primes whose homeliness is 3. |
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+0
13
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| 211, 223, 311, 337, 373, 389, 547, 571, 1123, 1153, 1319, 1931, 2237, 2311, 2341, 2371, 2557, 2719, 2797, 2953, 2971, 3167, 3181, 3191, 3257, 3313, 3329, 3347, 3449, 3457, 3461, 3463, 3517, 3541, 3547, 3557, 3571, 3643, 3701, 3709, 3727, 3733, 3739
(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, 8, 65, 437, 3233, 24579, ....
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EXAMPLE
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Only {4, 22, 211} -> 211, etc.
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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 = 3 - 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, 45]
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CROSSREFS
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Cf. A037274, A118756, A133959, A133956, A000014, A133958, A133962, A133964, A133966, A133968, A133970, A133972, A133974, A133976, A133978.
Sequence in context: A108406 A051268 A133959 this_sequence A031931 A087833 A096706
Adjacent sequences: A133957 A133958 A133959 this_sequence A133961 A133962 A133963
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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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