A083978 Smallest palindromic prime containing exactly n 7's.

7, 727, 72727, 77377, 1777771, 7772777, 17772727771, 777767777, 72777777727, 77777677777, 7767777777677, 7777774777777, 377777777777773, 777777727777777, 72777777777777727, 77777777677777777, 7776777777777776777, 717777777787777777717, 737777777777777777737

Offset: 1

Author

Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), May 21 2003

Keywords

• base
• nonn

Links

• Chai Wah Wu, Table of n, a(n) for n = 1..500

Crossrefs

Cf. A083972, A083973, A083974, A083975, A083976, A083977, A083979, A083980, A083981.

Programs

Mathematica

Table[d = 7; i = 1;
 While[ x = IntegerDigits[Prime[i]];
  x != Reverse[x] || Count[x, d] != n , i++];
FromDigits[x], {n, 1, 6}]  (* Robert Price, Mar 25 2019 *)

Extensions

Corrected and extended by Ray G. Opao, Sep 08 2004

Corrected and extended by Giovanni Resta, Feb 08 2006