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A089316 Prime worms [successive digit differences with absolute value of 2]. 2
131, 313, 353, 757, 797, 35353, 35753, 75797, 79757, 97579, 3131353, 3135313, 3531313, 7535797, 313131353, 313135313, 313579753, 353535313, 357531313, 357531353, 357535753, 357575753, 357975353, 753535357, 757975357, 975353579 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..25.

Carlos Rivera, Puzzle 246. The worm, The Prime Puzzles and Problems Connection.

FORMULA

Select prime numbers having the same first and last digits; if the uniform absolute value of successive digit differences is 2, add to sequence.

EXAMPLE

a(4)=797; first and last digits are 7; abs(7-9)=2; abs(9-7)=2; the worm is 7.

MATHEMATICA

pwQ[n_]:=Module[{idn=IntegerDigits[n]}, First[idn]==Last[idn]&&Union[Abs[ Differences[idn]]]=={2}]; Select[Prime[Range[50000000]], pwQ] (* Harvey P. Dale, Mar 26 2013 *)

CROSSREFS

Cf. A089291.

This is a subset of A048399. Cf. A089291, A089315, A089317, A048398-A048405.

Sequence in context: A132249 A033548 A117477 * A242846 A142129 A068680

Adjacent sequences:  A089313 A089314 A089315 * A089317 A089318 A089319

KEYWORD

easy,nonn,base

AUTHOR

Enoch Haga, Dec 25 2003

STATUS

approved

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Last modified June 28 02:57 EDT 2022. Contains 354903 sequences. (Running on oeis4.)