A219248 Numbers such that the absolute difference of any two adjacent (decimal) digits is prime.
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 13, 14, 16, 18, 20, 24, 25, 27, 29, 30, 31, 35, 36, 38, 41, 42, 46, 47, 49, 50, 52, 53, 57, 58, 61, 63, 64, 68, 69, 70, 72, 74, 75, 79, 81, 83, 85, 86, 92, 94, 96, 97, 130, 131, 135, 136, 138, 141, 142, 146, 147, 149, 161, 163, 164
Offset: 1
Links
- Michael S. Branicky, Table of n, a(n) for n = 1..10000 (terms 1..1000 from Harvey P. Dale)
- E. Angelini, Any digit-pair in S sums to a prime, SeqFan list, Apr 11 2013
Programs
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Mathematica
Select[Range[0,200],And@@PrimeQ[Abs[Differences[IntegerDigits[#]]]]&] (* Harvey P. Dale, Jun 06 2014 *)
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PARI
is_A219248(n)={!for(i=2,#n=digits(n),isprime(abs(n[i-1]-n[i]))||return)}
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Python
def ok(n): d = list(map(int, str(n))) return all(abs(d[i]-d[i-1]) in {2,3,5,7} for i in range(1, len(d))) print([k for k in range(164) if ok(k)]) # Michael S. Branicky, Sep 11 2024 -
Python
from itertools import count, islice def A219248gen(seed=None): # generator of terms nxt = {None:"123456789", "0":"2357", "1":"3468", "2":"04579", "3":"01568", "4":"12679", "5":"02378", "6":"13489", "7":"02459", "8":"1356", "9":"2467"} def bgen(d, seed=None): if d == 0: yield tuple(); return yield from ((i,)+t for i in nxt[seed] for t in bgen(d-1, seed=i)) yield 0 for d in count(1): yield from (int("".join(t)) for t in bgen(d, seed=seed)) print(list(islice(A219248gen(), 65))) # Michael S. Branicky, Sep 11 2024
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