A198486 Numbers with the property that all pairs of consecutive digits differ by 9.
1, 2, 3, 4, 5, 6, 7, 8, 9, 90, 909, 9090, 90909, 909090, 9090909, 90909090, 909090909, 9090909090, 90909090909, 909090909090, 9090909090909, 90909090909090, 909090909090909, 9090909090909090, 90909090909090909, 909090909090909090, 9090909090909090909
Offset: 1
Programs
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Mathematica
t = {1, 2, 3, 4, 5, 6, 7, 8, 9}; Do[AppendTo[t, 10*t[[-1]]]; AppendTo[t, 10*t[[-1]] + 9], {9}]; t (* T. D. Noe, Oct 22 2013 *) -
Python
def A198486(): print('Numbers whose consecutive digits differ by 9') for i in range(1, 100001): b, n = True, i if n > 9: while n > 9: a = abs((n // 10) % 10 - n % 10) if a != 9: b = False n = n // 10 if b: print(i, end=', ') return
Extensions
More terms from T. D. Noe, Oct 22 2013