A038211 Can express a(n) with the digits of a(n)^4 in order, only adding plus signs.
0, 1, 7, 10, 19, 22, 25, 27, 28, 34, 36, 37, 45, 52, 54, 55, 58, 61, 63, 64, 67, 72, 73, 76, 79, 81, 82, 85, 91, 100, 103, 106, 108, 109, 112, 115, 117, 118, 121, 124, 127, 133, 135, 142, 144, 145, 148, 153, 154, 157, 162, 163, 166, 169, 172, 175, 178, 180, 181
Offset: 1
Examples
a(6)=22 is in the sequence because 22^4=234256 and 2+3+4+2+5+6=22. a(8)=27 is in the sequence because 27^4=531441 and 5+3+14+4+1=27.
Links
- David A. Corneth, Table of n, a(n) for n = 1..10000 (first 5000 terms from Robert Israel)
Programs
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Maple
F:= proc(n,t) local d; option remember; if n = t then return true fi; if n < t then return false fi; for d from 1 to min(ilog10(t)+1,ilog10(n)+1) do if procname(floor(n/10^d), t - (n mod 10^d)) then return true fi od; false end proc: select(t -> F(t^4,t), [$0..1000]); # Robert Israel, Sep 06 2020
Extensions
Offset changed by Robert Israel, Sep 06 2020
Comments