OFFSET
1,1
COMMENTS
A007953(a(n)) = 5; number of repdigits = #{5,11111} = A242627(5) = 2. - Reinhard Zumkeller, Jul 17 2014
LINKS
Michael S. Branicky, Table of n, a(n) for n = 1..11628 (all terms through 15 digits; terms 1..1287 from Vincenzo Librandi and T. D. Noe, terms 1..462 from Vincenzo Librandi)
MATHEMATICA
Select[Range[10^4], Total[IntegerDigits[#]] == 5 &] (* Vincenzo Librandi, Mar 07 2013 *)
Union[Flatten[Table[FromDigits /@ Permutations[PadRight[s, 9]], {s, IntegerPartitions[5]}]]] (* T. D. Noe, Mar 08 2013 *)
PROG
(Magma) [n: n in [1..3010] | &+Intseq(n) eq 5 ]; // Vincenzo Librandi, Mar 07 2013
(Haskell)
a052219 n = a052219_list !! (n-1)
a052219_list = filter ((== 5) . a007953) [0..]
-- Reinhard Zumkeller, Jul 17 2014
(PARI) isok(n) = sumdigits(n) == 5; \\ Michel Marcus, Dec 28 2015
(Python)
from sympy.utilities.iterables import multiset_permutations
def auptodigs(maxdigits):
alst = [5]
for d in range(2, maxdigits+1):
fulldigset = list("0"*(d-1) + "1111122345")
for firstdig in "12345":
target_sum, restdigset = 5-int(firstdig), fulldigset[:]
restdigset.remove(firstdig)
for p in multiset_permutations(restdigset, d-1):
if sum(map(int, p)) == target_sum:
alst.append(int(firstdig+"".join(p)))
if int(p[0]) == target_sum: break
return alst
print(auptodigs(4)) # Michael S. Branicky, May 14 2021
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Henry Bottomley, Feb 01 2000
EXTENSIONS
Offset changed from Bruno Berselli, Mar 07 2013
STATUS
approved