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 A257787 Numbers n such that the sum of the digits of n to some power divided by the sum of the digits equal n. 1
 1, 2, 3, 4, 5, 6, 7, 8, 9, 37, 48, 415, 231591, 3829377463694454, 56407086228259246207394322684 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS The first nine terms are trivial, but then the terms become very rare. It appears that this sequence is finite. LINKS EXAMPLE 37 = (3^3+7^3)/(3+7). 231591 = (2^7+3^7+1^7+5^7+9^7+1^7)/(2+3+1+5+9+1). PROG (Python) def moda(n, a): ....kk = 0 ....while n > 0: ........kk= kk+(n%10)**a ........n =int(n//10) ....return kk def sod(n): ....kk = 0 ....while n > 0: ........kk= kk+(n%10) ........n =int(n//10) ....return kk for a in range (1, 10): ....for c in range (1, 10**6): ........if c*sod(c)==moda(c, a): ............print (a, c, moda(c, a), sod(c)) CROSSREFS Cf. A061209, A115518, A111434, A114135, A130680, A257784, A257768. Sequence in context: A080161 A257554 A270393 * A098771 A276810 A024659 Adjacent sequences:  A257784 A257785 A257786 * A257788 A257789 A257790 KEYWORD nonn,base,more AUTHOR Pieter Post, May 08 2015 EXTENSIONS a(14) from Giovanni Resta, May 09 2015 a(15) from Chai Wah Wu, Nov 30 2015 STATUS approved

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Last modified April 16 12:45 EDT 2021. Contains 343037 sequences. (Running on oeis4.)