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A070275 Numbers k such that the sum of the digits of k equals the sum of the prime divisors of k. 7
2, 3, 5, 7, 84, 160, 250, 336, 468, 735, 936, 975, 1344, 1375, 1408, 1600, 1694, 1872, 2352, 2401, 2500, 2625, 2808, 3744, 3920, 4116, 4913, 5145, 5616, 6084, 6318, 7296, 7497, 7695, 8424, 8624, 8664, 8704, 9126, 9639, 10240, 12168, 12636, 12675, 14896 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

If k=10^s*m is a term of the sequence where s > 0 and gcd(m,10)=1, then for each positive integer j, 10^j*m is in the sequence, because the sum of the digits of 10^j*k equals the sum of the digits of k and the sum of the distinct prime factors of 10^j*k equals the sum of the distinct prime factors of k. Also it is obvious that m isn't in the sequence. [Jahangeer Kholdi, Oct 07 2013]

LINKS

Giovanni Resta, Table of n, a(n) for n = 1..10000

MATHEMATICA

Rest[Select[Range[20000], Total[Transpose[FactorInteger[#]][[1]]] == Total[ IntegerDigits[#]] &]] (* Harvey P. Dale, Dec 15 2010 *)

PROG

(PARI) isok(n) = sumdigits(n) == vecsum(factor(n)[, 1]); \\ Michel Marcus, May 27 2018

CROSSREFS

Cf. A008472, A057531, A057532, A050689, A070274, A063737, A067077, A285494.

Sequence in context: A029976 A074310 A264576 * A171042 A068827 A289755

Adjacent sequences:  A070272 A070273 A070274 * A070276 A070277 A070278

KEYWORD

easy,nonn,base

AUTHOR

Benoit Cloitre, May 09 2002

STATUS

approved

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Last modified October 23 07:11 EDT 2019. Contains 328336 sequences. (Running on oeis4.)