A133972 Home primes whose homeliness is 9.

178069, 229751, 313613, 313739, 317741, 317903, 337457, 337853, 352489, 374587, 375743, 375997, 379103, 379187, 379397, 379997, 389971, 719239, 733391, 742283, 1128901, 1143113, 1148593, 1392143, 1911319, 2231051, 2331997, 2333329

Offset

1,1

Comments

Number of terms < 10^n: 0, 0, 0, 0, 0, 20, 146, ... .

Links

Table of n, a(n) for n=1..28.

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 = 9 - 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]

Crossrefs

Cf. A037274, A118756, A133971, A133956, A133957, A133958, A133960, A133962, A133964, A133966, A133968, A133970, A133974, A133976, A133978.

Sequence in context: A017567 A321815 A081867 * A233480 A233475 A243901

Adjacent sequences: A133969 A133970 A133971 * A133973 A133974 A133975

Keyword

nonn,base

Author

Robert G. Wilson v, Sep 30 2007

Status

approved