A102205 Iccanobirt semiprimes (15 of 15): Semiprime numbers in A102125.

4, 5071, 6313, 31591, 9853, 11733, 31865, 736481, 9834802, 5123383, 906334841, 312395329, 73044385753, 39216355244851, 353123779923181, 944016528715333, 901870160743125919, 3394064622591216338731, 798539095539570459224764519, 5844680137439021618014007903

Offset

1,1

Links

Table of n, a(n) for n=1..20.

Formula

a(n) = A102125(A102185(n)).

Mathematica

nxt[{a_, b_, c_}]:=With[{ir=IntegerReverse}, {b, c, ir[ir[a]+ir[b]+ir[c]]}]; Select[NestList[nxt, {0, 0, 1}, 200][[;; , 1]], PrimeOmega[#]==2&] (* Harvey P. Dale, Jul 22 2025 *)

Crossrefs

Cf. A001358, A102125, A102185, A102191-A102204.

Sequence in context: A344671 A203036 A306962 * A283663 A046360 A367942

Adjacent sequences: A102202 A102203 A102204 * A102206 A102207 A102208

Keyword

nonn,less,base

Author

Jonathan Vos Post and Ray Chandler, Dec 31 2004

Extensions

Offset changed to 1 and a(20) from Jinyuan Wang, Aug 14 2021

Status

approved