A340916 Integers m that have at least one divisor d such that d+m/d is a substring of m.

4, 272, 352, 400, 414, 418, 425, 432, 448, 450, 465, 490, 504, 518, 572, 585, 598, 720, 732, 744, 756, 768, 972, 1092, 1104, 1152, 1210, 1221, 1232, 1243, 1254, 1265, 1276, 1287, 1298, 1309, 1792, 1872, 1887, 1890, 1904, 1914, 1920, 1950, 1972, 2100, 2112, 2672

Offset: 1

Author

Michel Marcus, Jan 26 2021

Keywords

• nonn
• base

Comments

These are the resulting product strings in A339144.

Examples

			272 = 4*68 contains 4+68 = 72 as a substring, so 272 is a term.
		

Crossrefs

Cf. A339144, A340917.

Programs

Mathematica

q[n_] := AnyTrue[Divisors[n], SequenceCount[IntegerDigits[n], IntegerDigits[# + n/#]] > 0 &]; Select[Range[3000], q] (* Amiram Eldar, Jan 26 2021 *)

PARI

isok(n) = {fordiv(n, d, if (#strsplit(Str(n), Str(d+n/d)) > 1, return(1)); if (d^2 > n, return(0)););}