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A052221
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Numbers whose sum of digits is 7.
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37
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7, 16, 25, 34, 43, 52, 61, 70, 106, 115, 124, 133, 142, 151, 160, 205, 214, 223, 232, 241, 250, 304, 313, 322, 331, 340, 403, 412, 421, 430, 502, 511, 520, 601, 610, 700, 1006, 1015, 1024, 1033, 1042, 1051, 1060, 1105, 1114, 1123, 1132, 1141, 1150, 1204
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,1
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COMMENTS
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LINKS
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MATHEMATICA
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Select[Range[1500], Total[IntegerDigits[#]]==7&] (* Harvey P. Dale, Apr 11 2012 *)
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PROG
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(Haskell)
a052221 n = a052221_list !! (n-1)
a052221_list = filter ((== 7) . a007953) [0..]
(Python)
def ok(n): return sum(map(int, str(n))) == 7
(Python) # faster version generating initial segment
from sympy.utilities.iterables import multiset_permutations
def auptodigs(maxdigits):
alst = []
for d in range(1, maxdigits+1):
digset = "0"*(d-1) + "1111111222334567"
for p in multiset_permutations(digset, d):
if p[0] != '0' and sum(map(int, p)) == 7:
alst.append(int("".join(p)))
return alst
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CROSSREFS
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Cf. A011557 (1), A052216 (2), A052217 (3), A052218 (4), A052219 (5), A052220 (6), A052222 (8), A052223 (9), A052224 (10), A166311 (11), A235151 (12), A143164 (13), A235225(14), A235226 (15), A235227 (16), A166370 (17), A235228 (18), A166459 (19), A235229 (20).
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KEYWORD
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nonn,base,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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