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A061381 Smallest "inconsummate number" in base n greater than in the previous base. 1

%I #20 May 10 2023 10:42:45

%S 13,17,29,46,64,86,105,136,161,200,229,276,309,362,419,460,505,572,

%T 621,694,749,830,889,978,1054,1136,1205,1306,1381,1490,1569,1684,1769,

%U 1892,1999,2112,2205,2342,2441,2584,2689,2840,2949,3106,3269,3386,3505,3678

%N Smallest "inconsummate number" in base n greater than in the previous base.

%H Chai Wah Wu, <a href="/A061381/b061381.txt">Table of n, a(n) for n = 2..226</a>

%t n = 1; Do[ While[k = n; While[ Apply[ Plus, IntegerDigits[k, b] ]*n != k && k < 100n, k += n]; k != 100n, n++ ]; Print[n], {b, 2, 60} ]

%o (Python)

%o from functools import lru_cache

%o from itertools import count, combinations_with_replacement

%o from sympy.ntheory import digits

%o @lru_cache(maxsize=None)

%o def A061381(n):

%o for k in count((0 if n <= 2 else A061381(n-1))+1):

%o for l in count(1):

%o if (n-1)*l*k < n**(l-1):

%o return k

%o for d in combinations_with_replacement(range(n),l):

%o if (s:=sum(d)) > 0 and sorted(digits(s*k,n)[1:]) == list(d):

%o break

%o else:

%o continue

%o break # _Chai Wah Wu_, May 09 2023

%Y Cf. A052491.

%K base,easy,nice,nonn

%O 2,1

%A _Robert G. Wilson v_, Jun 08 2001

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Last modified April 24 20:08 EDT 2024. Contains 371963 sequences. (Running on oeis4.)