A259727 - OEIS

A259727

Sum of digits of a(n) equals the sum of digits of 3*a(n).

0, 9, 18, 27, 36, 45, 54, 72, 81, 90, 99, 108, 117, 135, 144, 171, 180, 189, 198, 207, 234, 270, 279, 288, 297, 342, 351, 360, 396, 405, 414, 441, 450, 459, 486, 495, 504, 540, 549, 558, 576, 585, 594, 639, 648, 657, 693, 702, 711, 720, 729, 756, 765, 783, 792

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

A007953(a(n)) = A007953(3*a(n)).

a(n) is a multiple of 9, but not all multiples of 9 belong to the sequence: e.g., 63 = 7*9: A007953(63) = 6 + 3 = 9, but A007953(3*63) = A007953(189) = 1 + 8 + 9 = 18.

LINKS

Table of n, a(n) for n=1..55.

EXAMPLE

99 belongs to the sequence, because A007953(99) = 18 = A007953(297) = A007953(3*99).

MATHEMATICA

Select[Range[0, 800], Total@ IntegerDigits@ # == Total@ IntegerDigits[3 #] &] (* Michael De Vlieger, Aug 05 2015 *)

PROG

(PARI) select(x->sumdigits(x)==sumdigits(3*x), vector(10^4, n, n)) \\ Joerg Arndt, Jul 04 2015

(Magma) [n: n in [0..800] | &+Intseq(n) eq &+Intseq(3*n)]; // Vincenzo Librandi, Aug 05 2015

CROSSREFS

Cf. A007953, A070279, A259728, A259729.

Sequence in context: A020336 A044834 A033006 * A118468 A206905 A083497

Adjacent sequences: A259724 A259725 A259726 * A259728 A259729 A259730

KEYWORD

nonn,easy,base

AUTHOR

Christina Steffan, Jul 04 2015

STATUS

approved