A062384 Positive numbers whose product of digits is 7 times their sum.

279, 297, 357, 375, 537, 573, 729, 735, 753, 792, 927, 972, 1447, 1474, 1744, 4147, 4174, 4417, 4471, 4714, 4741, 7144, 7414, 7441, 11367, 11376, 11637, 11673, 11736, 11763, 12247, 12274, 12427, 12472, 12724, 12742, 13167, 13176, 13617, 13671

Offset

1,1

Links

Harry J. Smith, Table of n, a(n) for n = 1..500

Example

1447 belongs to the sequence as (1*4*4*7)/(1+4+4+7) = 112/16 = 7.

Prog

(PARI) isok(n) = my(d=digits(n)); vecprod(d)==7*vecsum(d) \\ Mohammed Yaseen, Sep 09 2022
(Python)
from math import prod
def ok(n): d = list(map(int, str(n))); return n > 0 and prod(d) == 7*sum(d)
print([k for k in range(14000) if ok(k)]) # Michael S. Branicky, Sep 09 2022

Crossrefs

Cf. A011540, A034710, A062034, A062035, A062036, A062382, A062037, A062040, A062041, A062043, A062045.

Sequence in context: A228135 A188446 A251624 * A053345 A032505 A252855

Adjacent sequences: A062381 A062382 A062383 * A062385 A062386 A062387

Keyword

nonn,base,easy

Author

Amarnath Murthy, Jun 27 2001

Extensions

Corrected and extended by Larry Reeves (larryr(AT)acm.org), Jul 06 2001

Status

approved