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 A089365 Smallest prime whose product of digits is 2^n. 7

%I

%S 11,2,41,181,281,1481,881,4481,18481,48281,48481,228881,284881,828881,

%T 884881,4448881,4848881,18848881,24888881,48888841,88884881,188888881,

%U 888828881,848888881,4848488881,4488888881,18848888881,28888884881

%N Smallest prime whose product of digits is 2^n.

%H Chai Wah Wu, <a href="/A089365/b089365.txt">Table of n, a(n) for n = 0..1000</a>

%e a(8) = 24481 and the digital product is 2^8.

%t NextPrim[n_] := Block[{k = n + 1}, While[ ! PrimeQ[k], k++ ]; k]; a = Table[0, {24}]; p = 2; Do[q = Log[2, Times @@ IntegerDigits[p]]; If[q != 0 && IntegerQ[q] && a[[q]] == 0, a[[q]] = p; Print[q, " = ", p]]; p = NextPrim[p], {n, 1, 10^9}] (* _Robert G. Wilson v_, Nov 08 2003 *)

%t For a(8): a = Map[ FromDigits, Join[{0}, #, {1}] & /@ Permutations[{2, 8, 8 }]]; Min[ Select[a, PrimeQ[ # ] & ]] (* _Robert G. Wilson v_, Nov 08 2003 *)

%Y Cf. A088653, A090840, A091465, A090841, A089298.

%K base,nonn

%O 0,1

%A _Amarnath Murthy_, Nov 07 2003

%E Edited, corrected and extended by _Robert G. Wilson v_, Nov 08 2003

%E a(24)-a(25) corrected by _Chai Wah Wu_, Aug 15 2017

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Last modified June 17 15:38 EDT 2021. Contains 345085 sequences. (Running on oeis4.)