A276039 -id:A276039 - cp's OEIS frontend

A385324 Numbers whose digits are all powers of the same single-digit base.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 24, 28, 31, 33, 39, 41, 42, 44, 48, 51, 55, 61, 66, 71, 77, 81, 82, 84, 88, 91, 93, 99, 111, 112, 113, 114, 115, 116, 117, 118, 119, 121, 122, 124, 128, 131, 133, 139, 141, 142, 144, 148

Offset: 1

Stefano Spezia, Jun 25 2025

			84 is a term since its digits 8 and 4 are both powers of 2.

Stefano Spezia, Table of n, a(n) for n = 1..10000

Cf. A028846, A174813, A276037, A276039, A284293.

Cf. A385351 (subsequence)

Select[Range[0,148],SubsetQ[{0},dig=IntegerDigits[#]]||SubsetQ[{1,2,4,8},dig]||SubsetQ[{1,3,9},dig]||SubsetQ[{1,5},dig]||SubsetQ[{1,6},dig]||SubsetQ[{1,7},dig] &]

{0} U A028846 U A174813 U A276037 U A276039 U A284293.

A285011 Numbers with digits 7 and 9 only.

Original entry on oeis.org

7, 9, 77, 79, 97, 99, 777, 779, 797, 799, 977, 979, 997, 999, 7777, 7779, 7797, 7799, 7977, 7979, 7997, 7999, 9777, 9779, 9797, 9799, 9977, 9979, 9997, 9999, 77777, 77779, 77797, 77799, 77977, 77979, 77997, 77999, 79777, 79779, 79797, 79799, 79977, 79979

Offset: 1

Jaroslav Krizek, Apr 08 2017

Prime terms are in A020471.

Numbers with digits 7 and k only for k = 0 - 6 and 8 - 9: A204094 (k = 0), A276039 (k = 1), A284921 (k = 2), A143967 (k = 3), A284971 (k = 4), A284380 (k = 5), A256292 (k = 6), A256340 (k = 8), this sequence (k = 9).

[n: n in [1..100000] | Set(IntegerToSequence(n, 10)) subset {7, 9}];

Flatten@ Table[FromDigits /@ Tuples[{7, 9}, n], {n, 5}] (* Giovanni Resta, Apr 10 2017 *)

a(n,{p=[7,9]})={my(v=binary(n+1));fromdigits(vector(#v-1,i,p[2]*v[i+1]+p[1]*!v[i+1]))} \\ R. J. Cano, Apr 09 2017

def a(n): return int(bin(n+1)[3:].replace('0', '7').replace('1', '9'))
print([a(n) for n in range(1, 45)]) # Michael S. Branicky, Jul 09 2021

cp's OEIS Frontend

A385324 Numbers whose digits are all powers of the same single-digit base.

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