|
Search: id:A085324
|
|
|
| A085324 |
|
a(n) is the least exponent so that reverse[n^a(n)] is a prime number. a(n)=0 if no such exponent exists, namely when e.g. n=3k or =11k, k>1. |
|
+0
3
|
|
| 0, 1, 1, 2, 1, 0, 1, 8, 0, 0, 1, 0, 1, 1, 0, 1, 1, 0, 2, 1, 0, 0, 8, 0, 13, 47, 0, 2, 7, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 2, 2, 0, 5, 0, 0, 22, 15, 0, 6, 1, 0, 3, 10, 0, 0, 143, 0, 88, 12, 0, 4, 2, 0, 4, 8, 0, 39, 83, 0, 1, 1, 0, 1, 1, 0, 1, 0, 0, 1, 8, 0, 6, 11, 0, 2, 28, 0, 0, 2, 0, 1, 1, 0, 292, 1, 0, 1, 1
(list; graph; listen)
|
|
|
OFFSET
|
1,4
|
|
|
EXAMPLE
|
n=46: a(n)=22 means that reversion of 46^22 gives a prime: 6100744433653913942689966672393877083;
a(3k)=a(11k)=0 for k>1 because reversion does make prime from none of their powers.
|
|
MATHEMATICA
|
nd[x_, y_] := 10*x+y; tn[x_] := Fold[nd, 0, x]; bac[x_] := tn[Reverse[IntegerDigits[x]]] t={list without 3k and 11k numbers}; le=Length[t]; Table[f=1; Do[s=bac[Part[t, n]^k]; If[PrimeQ[s]&&Equal[f, 1], Print[{k, Part[t, n], s}]; f=0], {k, 1, 300}], {n, 1, le}]
|
|
CROSSREFS
|
Cf. A085325, A085298-A085300.
Sequence in context: A011126 A076422 A058998 this_sequence A062154 A110399 A112214
Adjacent sequences: A085321 A085322 A085323 this_sequence A085325 A085326 A085327
|
|
KEYWORD
|
base,nonn
|
|
AUTHOR
|
Labos E. (labos(AT)ana.sote.hu), Jul 02 2003
|
|
|
Search completed in 0.002 seconds
|
