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A067208
n is prime and remains prime when its leading digit is increased by one.
0
2, 13, 19, 31, 37, 43, 61, 73, 79, 97, 127, 139, 151, 157, 163, 181, 193, 211, 283, 331, 349, 367, 379, 409, 421, 457, 463, 487, 499, 541, 547, 577, 601, 619, 643, 661, 673, 709, 727, 739, 757, 787, 811, 829, 853, 877, 883, 919, 991, 997, 1039, 1063, 1069
OFFSET
1,1
EXAMPLE
Increasing the leading digit of 97 (prime) by one yields 107 (prime). Hence 97 is a term of the sequence.
MATHEMATICA
f[n_] := Block[{a = IntegerDigits[n] }, a[[1]] = a[[1]] + 1; Return[ FromDigits[a]]]; Select[ Range[1100], PrimeQ[ # ] && PrimeQ[ f[ # ]] & ]
CROSSREFS
Sequence in context: A168672 A297854 A298089 * A142348 A309663 A347259
KEYWORD
base,easy,nonn
AUTHOR
Joseph L. Pe, Feb 19 2002
EXTENSIONS
Edited and extended by Robert G. Wilson v, Feb 21 2002
STATUS
approved