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A240754
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Numbers k with digit_sum(k*k) - 1 = digit_sum((k+1)*(k+1)).
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4
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8, 26, 53, 98, 107, 143, 161, 170, 179, 188, 224, 233, 242, 260, 269, 278, 287, 296, 350, 368, 386, 404, 413, 431, 449, 476, 494, 503, 539, 548, 557, 584, 593, 629, 638, 647, 674, 683, 737, 746, 773, 791, 818, 827, 863, 872, 908, 926, 944, 998, 1007, 1043
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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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PROG
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(Haskell)
import Data.List (elemIndices)
a240754 n = a240754_list !! (n-1)
a240754_list = elemIndices (-1) a240752_list
(Python)
def ds(n): return sum(map(int, str(n)))
def ok(n): return ds(n*n) - 1 == ds((n+1)*(n+1))
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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