A294997 Numbers k such that the largest digit of k^3 is 7.

3, 14, 15, 23, 26, 30, 54, 55, 56, 63, 65, 67, 78, 91, 105, 111, 121, 126, 133, 135, 137, 140, 147, 150, 163, 167, 168, 173, 176, 188, 197, 226, 230, 245, 256, 258, 260, 273, 276, 291, 293, 295, 300, 318, 321, 343, 346, 375, 376, 385, 386, 397, 415, 417, 418, 424, 425, 488, 497

Offset

1,1

Comments

For any term a(n), all numbers of the form a(n)*10^k, k >= 0, are in this sequence. We could call "primitive" the terms not of this form, i.e., without trailing '0'.

Links

Kanishk Bhalerao, Table of n, a(n) for n = 1..300

Example

3 is in the sequence because the largest digit of 3^3 = 27 is 7.

Mathematica

Select[Range[500], Max[IntegerDigits[#^3]]==7&] (* Harvey P. Dale, Sep 10 2019 *)

Prog

(PARI) for(n=1, 2e3, vecmax(digits(n^3))==7&&print1(n", "))
(Python)
def ok(k): return max(str(k**3)) == "7"
print([k for k in range(10**3) if ok(k)]) # Michael S. Branicky, Jan 02 2026

Crossrefs

Cf. A295022 (the corresponding cubes).

Cf. A278937, A294664, A294665, A294996, A294998, A294999 (same for digit 3, ..., 9).

Cf. A000578 (the cubes).

Sequence in context: A391355 A070418 A178363 * A354740 A394220 A034120

Adjacent sequences: A294994 A294995 A294996 * A294998 A294999 A295000

Keyword

nonn,base,easy

Author

M. F. Hasler, Nov 13 2017

Status

approved