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A256824 Reverse concatenation of distinct digits of all divisors of n in base 10. 11
1, 21, 31, 421, 51, 6321, 71, 8421, 931, 5210, 1, 64321, 31, 7421, 531, 86421, 71, 986321, 91, 54210, 7321, 21, 321, 864321, 521, 6321, 97321, 87421, 921, 653210, 31, 864321, 31, 74321, 7531, 9864321, 731, 98321, 931, 854210, 41, 764321, 431, 421, 95431, 64321 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Concatenation of elements of set of all digits of all divisors of n in decreasing order in base 10.
There are precisely 512 distinct terms of this sequence - see A256825 (possible values of a(n) in increasing order).
Minimal term is 1, maximal term is 9876543210.
Numbers n such that a(n) = 1 are in A243534, numbers n such that a(n) = 9876543210 are in A095050.
See A256826 - the smallest numbers k such that a(k) = A256825(n).
LINKS
EXAMPLE
For n = 12; list of divisors of 12 in base 10: 1, 2, 3, 4, 6, 12 contains five distinct digits (1, 2, 3, 4, 6) whose reverse concatenation is 64321.
MATHEMATICA
Table[FromDigits[Reverse[Union[Flatten[IntegerDigits[Divisors[n]]]]]], {n, 100}] (* Ivan N. Ianakiev, Apr 14 2015 *)
PROG
(Magma) [Seqint(Setseq(Set(Sort(&cat[Intseq(d): d in Divisors(n)])))): n in [1..100]]
(PARI) a(n) = {my(v = []); fordiv(n, d, v = vecsort(concat(v, digits(d)), , 8)); subst(Polrev(v), x, 10); } \\ Michel Marcus, Apr 11 2015
CROSSREFS
Sequence in context: A208293 A032013 A324489 * A176558 A243360 A068657
KEYWORD
nonn,base
AUTHOR
Jaroslav Krizek, Apr 10 2015
STATUS
approved

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Last modified July 20 18:09 EDT 2024. Contains 374459 sequences. (Running on oeis4.)