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A296451
Anagraprod Integers. Integers N that reproduce their multiset of digits when all the products of two successive digits of N are done (and considered together).
3
135, 162, 261, 531, 1135, 1162, 1326, 1350, 1620, 2135, 2162, 2610, 2611, 2612, 2613, 2614, 2615, 2616, 2617, 2618, 2619, 3135, 3162, 4135, 4162, 5135, 5162, 5310, 5311, 5312, 5313, 5314, 5315, 5316, 5317, 5318, 5319, 6135, 6162, 6231, 7135, 7162, 8135, 8162, 9135, 9162, 11135, 11162, 11326, 11350, 11620, 13260, 13500, 16200, 21135, 21162, 21326, 21350, 21620, 22134, 23126, 26100, 26110, 26111, 26112, 26113, 26114, 26115
OFFSET
1,1
COMMENTS
The sequence is infinite as each term can be extended with as many zeros as wanted. The name "anagraprod numbers" comes from "anagram by product". The "anagrasum numbers" are A296521.
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..500 (first 304 terms from Georges Brougnard)
EXAMPLE
135 reproduces the digits 1, 3 and 5 (in a different order) when the products 1*3=3 and 3*5=15 are done. The same with 162 which reproduces the digit 1, 6 and 2 when the products 1*6=6 and 6*2=12 are made.
1135 is a term: 1*1 = 1, 1*3 = 3, 3*5 = 15 -> multiset {1,1,3,5}.
2162 is a term: 2*1 = 2, 1*6 = 6, 6*2 = 12 -> multiset {1,2,2,6}.
MATHEMATICA
A296451Q[k_] := Sort[Flatten[IntegerDigits[Times @@@ Partition[#, 2, 1]]]] == Sort[#] & [IntegerDigits[k]];
Select[Range[10000], A296451Q] (* Paolo Xausa, Nov 30 2024 *)
PROG
(Python)
def ok(n):
s = str(n)
d = list(map(int, s))
sums = [d[i]*d[i+1] for i in range(len(s)-1)]
return sorted(s) == sorted("".join(str(t) for t in sums))
print([k for k in range(10**5) if ok(k)]) # Michael S. Branicky, Nov 27 2024
CROSSREFS
Sequence in context: A235809 A066176 A025363 * A096593 A050215 A358778
KEYWORD
nonn,base
AUTHOR
Eric Angelini and Georges Brougnard, Dec 13 2017
STATUS
approved