A048398 Primes with consecutive digits that differ exactly by 1.
2, 3, 5, 7, 23, 43, 67, 89, 101, 787, 4567, 12101, 12323, 12343, 32321, 32323, 34543, 54323, 56543, 56767, 76543, 78787, 78989, 210101, 212123, 234323, 234343, 432121, 432323, 432343, 434323, 454543, 456767, 654323, 654343, 678767, 678989
Offset: 1
References
- J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 67, p. 23, Ellipses, Paris 2008.
Links
- Chai Wah Wu, Table of n, a(n) for n = 1..10000 (terms n = 1..1500 from Zak Seidov)
Crossrefs
Programs
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Haskell
a048398 n = a048398_list !! (n-1) a048398_list = filter ((== 1) . a010051') a033075_list -- Reinhard Zumkeller, Feb 21 2012, Nov 04 2010 (Python 3.2 or higher) from itertools import product, accumulate from sympy import isprime A048398_list = [2,3,5,7] for l in range(1,17): for d in [1,3,7,9]: dlist = [d]*l for elist in product([-1,1],repeat=l): flist = [str(d+e) for d,e in zip(dlist,accumulate(elist)) if 0 <= d+e < 10] if len(flist) == l and flist[-1] != '0': n = 10*int(''.join(flist[::-1]))+d if isprime(n): A048398_list.append(n) A048398_list = sorted(A048398_list) # Chai Wah Wu, May 31 2017
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Mathematica
Select[Prime[Range[10000]], # < 10 || Union[Abs[Differences[IntegerDigits[#]]]] == {1} &]
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