A283608 Numbers whose largest decimal digit is 5.

5, 15, 25, 35, 45, 50, 51, 52, 53, 54, 55, 105, 115, 125, 135, 145, 150, 151, 152, 153, 154, 155, 205, 215, 225, 235, 245, 250, 251, 252, 253, 254, 255, 305, 315, 325, 335, 345, 350, 351, 352, 353, 354, 355, 405, 415, 425, 435, 445, 450, 451, 452, 453, 454

Offset

1,1

Comments

Numbers n such that A054055(n) = 5.

Number of terms less than 10^n is 6^n - 5^n.

Subsequence of A011535. - David A. Corneth, Mar 25 2017

Prime terms are in A106097.

Links

Muniru A Asiru, Table of n, a(n) for n = 1..5000

Mathematica

Select[Range[1000], Max[IntegerDigits[#]] == 5 &] (* Giovanni Resta, Mar 19 2017 *)

Prog

(Magma) [n: n in [1..100000] | Maximum(Setseq(Set(Sort(&cat[Intseq(n)])))) eq 5];
(PARI) for(n=1, 500, if(vecmax(digits(n))==5, print1(n, ", "))) \\ Indranil Ghosh, Mar 19 2017
(PARI) nxt(n) = {my(d = digits(n), i, j=0, t=0); forstep(i=#d, 1, -1, if(d[i]!=5, j=i; break)); if(j>0, d[j]++; if(d[j]==5, for(k=j+1, #d, d[k]=0)); if(j<#d && d[j+1]==5, for(k=j+1, #d-1, d[k]=0)); for(k=1, j-1, if(d[k]==5, for(i=j+1, #d, d[i] = 0); break)), d = vector(#d+1); d[1]=1; d[#d]=5); sum(i=1, #d, d[i]*10^(#d-i))} \\ David A. Corneth, Mar 25 2017
(Python)
from sympy.ntheory.factor_ import digits
print([n for n in range(1, 501) if max(digits(n)[1:])==5]) # Indranil Ghosh, Mar 19 2017
(GAP) Filtered([1..500], n->Maximum(ListOfDigits(n))=5); # Muniru A Asiru, Feb 27 2019

Crossrefs

Cf. A011535, A054055, A106097.

Cf. Sequences of numbers whose largest decimal digit is k (for k = 1..9): A007088 (k = 1), A277964 (k = 2), A277965 (k = 3), A277966 (k = 4), this sequence (k = 5), A283609 (k = 6), A283610 (k = 7), A283611 (k = 8), A011539 (k = 9).

Sequence in context: A075336 A031236 A011535 * A043509 A121025 A277592

Adjacent sequences: A283605 A283606 A283607 * A283609 A283610 A283611

Keyword

nonn,base,easy

Author

Jaroslav Krizek, Mar 19 2017

Status

approved