A366960 Numbers whose difference between the largest and smallest digits is equal to 3.

14, 25, 30, 36, 41, 47, 52, 58, 63, 69, 74, 85, 96, 103, 114, 124, 130, 134, 141, 142, 143, 144, 203, 214, 225, 230, 235, 241, 245, 252, 253, 254, 255, 300, 301, 302, 303, 310, 314, 320, 325, 330, 336, 341, 346, 352, 356, 363, 364, 365, 366, 411, 412, 413, 414

Offset

1,1

Comments

The number of n-digit terms of this sequence is 27*4^(n-1) - 41*3^(n-1) + 7*2^n.

Links

Stefano Spezia, Table of n, a(n) for n = 1..10000

Mathematica

Select[Range[415], Max[d=IntegerDigits[#]]-Min[d]==3 &]

Prog

(Python)
def ok(n): return max(d:=list(map(int, str(n))))-min(d) == 3
print([k for k in range(420) if ok(k)]) # Michael S. Branicky, Oct 30 2023
(Python)
from itertools import chain, count, islice, combinations_with_replacement
from sympy.utilities.iterables import multiset_permutations
def A366960_gen(): # generator of terms
    return chain.from_iterable(sorted(int(''.join(str(d) for d in t)) for a in range(7) for c in combinations_with_replacement(range(a, a+4), l) for t in multiset_permutations((a, a+3)+c) if t[0]) for l in count(0))
A366960_list = list(islice(A366960_gen(), 30)) # Chai Wah Wu, Nov 10 2023
(PARI) isok(n) = my(d=digits(n)); vecmax(d) - vecmin(d) == 3; \\ Michel Marcus, Nov 05 2023

Crossrefs

Cf. A037904.

Cf. A010785 (difference = 0), A366958 (difference = 1), A366959 (difference = 2), A366961 (difference = 4), A366962 (difference = 5), A366963 (difference = 6), A366964 (difference = 7), A366965 (difference = 8), A366966 (difference = 9).

Sequence in context: A140499 A068365 A154038 * A061923 A031075 A020227

Adjacent sequences: A366957 A366958 A366959 * A366961 A366962 A366963

Keyword

nonn,base,easy

Author

Stefano Spezia, Oct 30 2023

Status

approved