A032745 - OEIS

A032745

Super-5 Numbers (5 * n^5 contains substring '55555' in its decimal expansion).

4602, 5517, 7539, 12955, 14555, 20137, 20379, 26629, 32767, 35689, 35825, 37706, 46020, 46715, 51988, 55170, 66344, 73338, 73974, 75390, 76157, 86025, 91497, 105852, 114488, 129550, 132234, 145550, 146399, 158651, 160897, 171673, 174782, 176988, 184471, 188421, 191261, 192607

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OFFSET

1,1

COMMENTS

The terms a({15, 25, 34}) = {51988, 114488, 176988} are such that 5*a(n)^5 == 55555840 (mod 10^8). Therefore any number congruent to one of these, modulo 5*10^5, is also in the sequence. Of course, for any a(n) in the sequence, any a(n)*10^k, k >= 0, is also in the sequence. - M. F. Hasler, Jul 16 2024

REFERENCES

C. A. Pickover, "Keys to Infinity", New York: Wiley, p. 7, 1995.

LINKS

Table of n, a(n) for n=1..38.

Giovanni Resta, super-d numbers, personal web site "Numbers Aplenty", 2013

Eric Weisstein's World of Mathematics, Super-d Number

MATHEMATICA

Select[Range[200000], SequenceCount[IntegerDigits[5#^5], {5, 5, 5, 5, 5}]>0&] (* Harvey P. Dale, Jul 16 2016 *)

PROG

(PARI) select( {is_A032745(n)=is_A032743(n, 5)}, [1..2^18]) \\ M. F. Hasler, Jul 16 2024

CROSSREFS

Cf. A014569, A032743-A032749.