A133978 Home primes whose homeliness is 12.

378997, 777643, 3127979, 3127997, 3136607, 3173761, 3374729, 3377999, 3759263, 3774161, 3791387, 3943967, 7342469, 7521641, 7540541, 7767709

Offset

1,1

Comments

Number of terms < 10^n: 0, 0, 0, 0, 0, 2, 16, ... .

Links

Table of n, a(n) for n=1..16.

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 = 12 - 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, 31]

Crossrefs

Cf. A037274, A118756, A133977, A133956, A133957, A133958, A133960, A133962, A133964, A133966, A133968, A133970, A133972, A133974, A133976.

Sequence in context: A238078 A133975 A133977 * A159265 A133976 A286009

Adjacent sequences: A133975 A133976 A133977 * A133979 A133980 A133981

Keyword

nonn,base,more

Author

Robert G. Wilson v, Sep 30 2007

Status

approved