A334679 - OEIS

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A334679

Numbers k such that k*p is divisible by k+p, where p > 0 and p = A007954(k) = the product of digits of k.

2, 4, 6, 8, 24, 36, 63, 456, 495, 3276, 6624, 7497, 8832, 19728, 23976, 127488, 167328, 273525, 274995, 297675, 576975, 661248, 797769, 853776, 1323648, 1378272, 1491264, 1886976, 3483648, 3679263, 3787749, 4644864, 6386688, 7886592, 7888896, 12841472, 15974784, 16224768

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

OFFSET

1,1

LINKS

Giovanni Resta, Table of n, a(n) for n = 1..95 (terms < 3.5*10^14)

EXAMPLE

8 is a term as p = 8 and 8*8 = 64 is divisible by 8+8 = 16.

3276 is a term as p = 3*2*7*6 = 252 and 3276*252 = 825552 is divisible by 3276+252 = 3528.

3787749 is a term as p = 3*7*8*7*7*4*9 = 296352 and 3787749*296352 = 1122506991648 is divisible by 3787749+296352 = 4084101.

MATHEMATICA

Select[Range[10^6], (p = Times @@ IntegerDigits@ #; p > 0 && Mod[# p, # + p] == 0) &] (* Giovanni Resta, May 08 2020 *)

PROG

(PARI) isok(m) = my(p=vecprod(digits(m))); p && !((m*p) % (m+p)); \\ Michel Marcus, May 08 2020

CROSSREFS

Cf. A330880, A334803, A007954, A049102, A085124.

Subsequence of A052382.

Sequence in context: A119260 A219616 A067732 * A222712 A117912 A092047

Adjacent sequences: A334676 A334677 A334678 * A334680 A334681 A334682

KEYWORD

nonn,base

AUTHOR

Scott R. Shannon, May 08 2020

STATUS

approved