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A133962
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Home primes whose homeliness is 4.
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12
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379, 2347, 2383, 2389, 3331, 3359, 3373, 3719, 3767, 4397, 4759, 7331, 7457, 7523, 7547, 7823, 11251, 13883, 17137, 17317, 19157, 19181, 22367, 22397, 23131, 23173, 23197, 23311, 23593, 23677, 23767, 23911, 29101, 31063, 31123, 31181, 31189
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Number of terms < 10^n: 0, 0, 1, 16, 146, 1085, 8522, ....
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EXAMPLE
| Only (42,74,237,379) -> 379, etc.
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MATHEMATICA
| 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 = 4 - 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
| Cf. A037274, A118756, A133961, A133956, A000014, A133958, A133960, A133964, A133966, A133968, A133970, A133972, A133974, A133976, A133978.
Sequence in context: A161612 A142752 A133961 * A027503 A099728 A206349
Adjacent sequences: A133959 A133960 A133961 * A133963 A133964 A133965
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KEYWORD
| nonn
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AUTHOR
| Robert G. Wilson v (rgwv(AT)rgwv.com), Sep 30 2007
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