A334557 Numbers m such that m = p^2 + k^2, with p > 0, where p = A007954(m) = the product of digits of m.

1, 13, 41, 61, 125, 212, 281, 613, 1156, 1424, 2225, 3232, 3316, 4113, 11125, 11281, 11525, 12816, 14913, 16317, 16441, 19125, 21284, 21625, 24128, 25216, 27521, 31525, 53125, 56116, 61321, 65161, 71325, 82116, 82217, 83521, 84313, 111812, 113125, 113625, 115336, 115681, 117125, 118372

Offset: 1

Author

Scott R. Shannon, May 06 2020

Keywords

• nonn
• base

Examples

			13 is a term as p = 1*3 = 3 and 13 = 3^2 + 2^2.
281 is a term as p = 2*8*1 = 16 and 281 = 16^2 + 5^2.
118372 is a term as p = 1*1*8*3*7*2 = 336 and 118372 = 336^2 + 74^2.
		

Links

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

Crossrefs

Cf. A007954, A000404, A078134, A334542, A334558.

Programs

PARI

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