A102177 Iccanobirt semiprime indices (7 of 15): Indices of semiprime numbers in A102117.

5, 9, 22, 29, 33, 38, 41, 54, 60, 71, 82, 100, 107, 175, 180, 193, 217, 258, 259, 282, 295, 360, 382

Offset

1,1

Links

Table of n, a(n) for n=1..23.

Formula

A102117(a(n)) = A102197(n).

Mathematica

nxt[{a_, b_, c_}]:={b, c, Total[IntegerReverse/@{a, b, c}]}; Flatten[ Position[ NestList[nxt, {0, 0, 1}, 220][[All, 1]], _?(PrimeOmega[#] == 2&)]]-1 (* Harvey P. Dale, Dec 30 2018 *)

Crossrefs

Cf. A001358, A102117, A102171-A102185, A102197.

Sequence in context: A146476 A110200 A063404 * A299266 A219521 A215178

Adjacent sequences: A102174 A102175 A102176 * A102178 A102179 A102180

Keyword

nonn,more,less,base

Author

Jonathan Vos Post and Ray Chandler, Dec 31 2004

Extensions

a(17) from Robert Price, Nov 09 2018

Offset changed to 1 and a(18)-a(23) from Jinyuan Wang, Aug 12 2021

Status

approved