A090933 Primes such that most significant digit swapped with all other digits yields primes.

2, 3, 5, 7, 11, 13, 17, 31, 37, 71, 73, 79, 97, 101, 107, 113, 131, 149, 167, 179, 181, 191, 199, 311, 337, 373, 389, 701, 709, 727, 733, 739, 751, 757, 787, 797, 907, 919, 937, 941, 953, 991, 1009, 1013, 1031, 1049, 1051, 1091, 1123, 1181, 1319, 1321, 1381

Offset: 1

Author

Amarnath Murthy, Dec 29 2003

Keywords

• base
• nonn

Comments

Appears to be denser than A090934, where the least significant digit is swapped.

Examples

			149 is a term as 149, 419 & 491 are all prime.
		

Crossrefs

Cf. A090934.

Programs

Mathematica

fQ[n_] := Block[{a = c = IntegerDigits[n], b = {}, l = Floor[ Log[10, n] + 1]}, Do[ a = c; {a[[1]], a[[i]]} = {a[[i]], a [[1]]}; AppendTo[b, FromDigits[a]], {i, 1, l}]; Union[ PrimeQ[b]] == {True}]; Select[ Prime[ Range[ 270]], fQ[ # ] &] (* Ed Pegg Jr, Jan 15 2004 *)

Extensions

Edited, corrected and extended by Robert G. Wilson v, Jan 15 2004