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A392864
a(n) = Sum_{i=1..n} (A392614(1+n) mod prime(i))*A002110(i-1).
5
0, 1, 5, 11, 191, 1007, 14867, 255107, 9129053, 67327193, 4529184593, 166271515343, 4779162788333, 138352449214913, 3789355611541433, 239279059581601973, 24834870363121258373, 1393579526405103137033, 18698422677793016888663, 2129889287147118494587523, 536495754760605278294365643, 21180306469448466834088735073
OFFSET
0,3
COMMENTS
By definition, the resulting primorial base expansions (see examples) never contain any zeros for n > 0, not even "hidden leading zeros", i.e., this is a subsequence of A328574 and also A267263(a(n)) == n for all n.
EXAMPLE
n a(n) A049345(a(n))
---+---------------------------------------------------------------------
0 | 0, 0,
1 | 1, 1,
2 | 5, 2:1,
3 | 11, 1:2:1,
4 | 191, 6:1:2:1,
5 | 1007, 4:5:2:2:1,
6 | 14867, 6:4:5:2:2:1,
7 | 255107, 8:6:4:5:2:2:1,
8 | 9129053, 17:14:12:10:4:3:2:1,
9 | 67327193, 6:17:14:12:10:4:3:2:1,
10 | 4529184593, 20:6:17:14:12:10:4:3:2:1,
11 | 166271515343, 25:20:6:17:14:12:10:4:3:2:1,
12 | 4779162788333, 23:25:20:6:17:14:12:10:4:3:2:1,
13 | 138352449214913, 18:23:25:20:6:17:14:12:10:4:3:2:1,
14 | 3789355611541433, 12:18:23:25:20:6:17:14:12:10:4:3:2:1,
15 | 239279059581601973, 18:12:18:23:25:20:6:17:14:12:10:4:3:2:1,
16 | 24834870363121258373, 40:18:12:18:23:25:20:6:17:14:12:10:4:3:2:1,
etc.
The digits in the primorial base expansion of the terms, from term a(8) up to term a(11980-1), when read from right to left, give the terms of sequence A392862, and at n=11980, the pattern changes again.
Compare to the pattern in A392863.
PROG
(PARI)
A002110(n) = prod(i=1, n, prime(i));
A143293(n) = { if(n==0, return(1)); my(P=1, s=1); forprime(p=2, prime(n), s+=P*=p); s; };
A392614(n) = if(!n, n, my(pr=A002110(n)); for(k=A143293(n-1), oo, if(1==gcd(k, pr), return(k))));
A392864(n) = { my(x=A392614(1+n)); sum(i=1, n, (x%prime(i))*A002110(i-1)); };
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Antti Karttunen, Jan 26 2026
STATUS
approved