A247095 Smallest number m such that A250030(m) = n.

8, 7, 6, 5, 13, 30, 29, 157, 317, 626, 3095, 6637, 26833, 145687, 461938, 1068037, 16007153, 54690697

Offset: 1

Author

Reinhard Zumkeller, Nov 18 2014

Keywords

• nonn
• more

Crossrefs

Cf. A008474, A250030.

Programs

Haskell

import Data.List (elemIndex); import Data.Maybe (fromJust)
a247095 = (+ 5) . fromJust . (`elemIndex` a250030_list)

PARI

A008474(n)=my(f=factor(n)); sum(i=1, #f~, f[i, 1]+f[i, 2]);
f(n)=my(k); while(n!=5, n=A008474(n); k++); k; \\ A250030
a(n) = my(k=5); while(f(k) != n, k++); k; \\ Michel Marcus, Feb 05 2022

Formula

A250030(a(n)) = n and A250030(m) != n for m < a(n).

Extensions

a(17)-a(18) from Michel Marcus, Feb 05 2022