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%I #21 Oct 29 2022 06:02:16
%S 10,12,21,23,32,34,43,45,54,56,65,67,76,78,87,89,98,100,101,102,103,
%T 104,105,106,107,108,109,110,112,120,121,122,123,124,125,126,127,128,
%U 129,132,134,143,145,154,156,165,167,176,178,187,189,198,201,210,211,212,213
%N Numbers in which at least one pair of adjacent digits differ by 1.
%F a(n) = n + O(x^0.915), where the exponent is the log(k)/log(10) with k the largest root of x^5 - 9x^4 + 4x^3 + 21x^2 - 9x - 5. - _Charles R Greathouse IV_, Mar 11 2014
%e 1998 is a term because 8 and 9 differ by 1.
%t Select[Range[250],MemberQ[Abs[Differences[IntegerDigits[#]]],1]&] (* _Harvey P. Dale_, Apr 07 2018 *)
%o (PARI) isok(n) = (d = digits(n)) && (sum(i=1, #d-1, abs(d[i] - d[i+1])==1) >= 1); \\ _Michel Marcus_, Mar 11 2014
%K base,easy,nonn
%O 1,1
%A Anonymous, Apr 15 2003
%E 120 added by _Zak Seidov_, Mar 11 2014
%E Name clarified by _Jon E. Schoenfield_, Oct 29 2022
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