A286377 a(n) = A278243(n^2).

1, 2, 2, 60, 2, 2520, 60, 138600, 2, 87318000, 2520, 189189000, 60, 792148896000000, 138600, 70756686000, 2, 2288271225240000, 87318000, 944154902157667200000000, 2520, 20388496616888400000000, 189189000, 127170673342713000000, 60, 701323506627727183200000000, 792148896000000, 21149759041410320377056000000000000000, 138600

Offset

0,2

Comments

Observation: the restricted growth sequence computed for this sequence seems to give A103391 (apart from the fact that the latter uses starting offset 1 instead of 0. Checked up to n=2048). If this holds, then A103391 works as a more practical filtering sequence (than this sequence, with its huge terms) matching for example to sequences like A286387. Compare also to A286378.

Links

Antti Karttunen, Table of n, a(n) for n = 0..256

Index entries for sequences related to Stern's sequences

Formula

a(n) = A278243(A000290(n)) = A278243(n^2).

Prog

(PARI)
A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ This function from Charles R Greathouse IV, Aug 17 2011
A003961(n) = my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); \\ This function from Michel Marcus
A260443(n) = if(n<2, n+1, if(n%2, A260443(n\2)*A260443(n\2+1), A003961(A260443(n\2))));
A278243(n) = A046523(A260443(n));
A286377(n) = A278243(n*n);
for(n=0, 256, write("b286377.txt", n, " ", A286377(n)));
(Scheme) (define (A286377 n) (A278243 (* n n)))

Crossrefs

Cf. A000290, A103391, A278243, A286374, A286378, A286387.

Sequence in context: A379866 A368867 A378302 * A187024 A274477 A231808

Adjacent sequences: A286374 A286375 A286376 * A286378 A286379 A286380

Keyword

nonn

Author

Antti Karttunen, May 09 2017

Status

approved