|
Search: id:A133962
|
|
|
| A133962 |
|
Home primes whose homeliness is 4. |
|
+0
13
|
|
| 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; listen)
|
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
Number of terms < 10^n: 0, 0, 1, 16, 146, 1085, 8522, ....
|
|
EXAMPLE
|
Only (42,74,237,379) -> 379, etc.
|
|
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]
|
|
CROSSREFS
|
Cf. A037274, A118756, A133961, A133956, A000014, A133958, A133960, A133964, A133966, A133968, A133970, A133972, A133974, A133976, A133978.
Sequence in context: A058995 A142752 A133961 this_sequence A027503 A099728 A023910
Adjacent sequences: A133959 A133960 A133961 this_sequence A133963 A133964 A133965
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Robert G. Wilson v (rgwv(AT)rgwv.com), Sep 30 2007
|
|
|
Search completed in 0.002 seconds
|
