A334542 Numbers m such that m^2 = p^2 + k^2, with p > 0, where p = A007954(m) = the product of digits of m.

1, 2, 3, 4, 5, 6, 7, 8, 9, 58, 85, 375, 666, 1968, 1998, 3578, 3665, 3891, 4658, 4995, 6675, 7735, 18434, 27475, 28784, 46692, 56763, 58896, 59577, 59949, 76965, 186633, 186673, 795848, 949968, 965667, 1339575, 1587616, 1929798, 2765388, 2989584, 3674195, 4763568, 5762784, 36741656, 58988961, 134369685, 188959392

Offset

1,2

Links

Giovanni Resta, Table of n, a(n) for n = 1..140 (terms < 2*10^13)

Example

58 is a term as p = 5*8 = 40 and 58^2 = 3364 = 40^2 + 42^2.
3891 is a term as p = 3*8*9*1 = 216 and 3891^2 = 15139881 = 216^2 + 3885^2.

Prog

(PARI) isok(m) = my(p=vecprod(digits(m))); p && issquare(m^2 - p^2); \\ Michel Marcus, May 06 2020

Crossrefs

Cf. A007954, A000404, A078134, A334557, A334558.

Subsequence of A052382 (zeroless numbers).

Sequence in context: A062388 A070244 A302500 * A102493 A024661 A107070

Adjacent sequences: A334539 A334540 A334541 * A334543 A334544 A334545

Keyword

nonn,base

Author

Scott R. Shannon, May 05 2020

Status

approved