|
%I #36 Sep 19 2021 18:36:18
%S 8,9,10,17,19,26,28,35,37,44,46,53,55,62,64,71,73,80,82,89,91,98,100,
%T 107,109,116,118,125,127,134,136,143,145,152,154,161,163,170,172,179,
%U 181,188,190,197,199,206,208,215,217,224,226,233,235,242,244,251,253
%N Numbers which are the digital sum of the cube of some prime.
%C A235398 sorted and duplicates removed.
%F Conjecture: for n > 4, a(n) = a(n-2) + 9.
%F Conjecture: a(n) = (1/4)*(-1)^n*(9*(-1)^n*(2*n-1) + 5), n >= 3. - _Bill McEachen_, Feb 13 2021
%t Total[IntegerDigits[#]] & /@ (Prime[Range[5000000]]^3) // Union (* The program generates the first 39 terms of the sequence. To generate more, increase the Range constant. *) (* _Harvey P. Dale_, Sep 19 2021 *)
%o (PARI) list(maxx)={v=List();n=2; while(n<=maxx,q=n^3;summ=sumdigits(q);
%o if(setsearch(v,summ)<1,listput(v,summ));n=nextprime(n+1));vecsort(v,,8) ;} \\ _Bill McEachen_, Jan 29 2014
%Y Cf. A235398, A004164, A007953, A123157.
%K nonn,base
%O 1,1
%A _Antonio Graciá Llorente_, Jan 09 2014
%E a(37)-a(57) from _Lars Blomberg_, Feb 10 2016
|
