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A338235 Numbers k such that k + the sum of the 4th powers of the decimal digits of k is a square. 0
20, 47, 104, 113, 228, 255, 333, 544, 632, 743, 1054, 1122, 1518, 1762, 1901, 2071, 3617, 4317, 4432, 4456, 4513, 4557, 4727, 4927, 5000, 5058, 5080, 5173, 5473, 5847, 6047, 6767, 6832, 7247, 7408, 7453, 7487, 7518, 7921, 7997, 8127, 8958, 9208, 9487, 10917 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..45.

EXAMPLE

20 is a member since 2^4 + 0^4 + 20 = 6^2,

47 is a member since 4^4 + 7^4 + 47 = 52^2,

104 is a member since 1^4 + 0^4 + 4^4 = 104 = 19^2,

113 is a member since 1^4 + 1^4 + 3^4 + 113 = 14^2.

MAPLE

filter:= proc(n) local L, k;

  issqr(n + add(t^4, t=convert(n, base, 10)))

end proc:

select(filter, [$1..20000]); # Robert Israel, Jan 30 2021

CROSSREFS

Cf. A055013, A329179, A329386.

Sequence in context: A234266 A234259 A135286 * A177725 A264444 A053245

Adjacent sequences:  A338232 A338233 A338234 * A338236 A338237 A338238

KEYWORD

base,nonn

AUTHOR

Will Gosnell, Jan 30 2021

STATUS

approved

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Last modified September 16 23:53 EDT 2021. Contains 347477 sequences. (Running on oeis4.)