OFFSET
1,1
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..10001
FORMULA
a(n) = a(n-P) + S = a((n-1)%P + 1) + S*floor((n-1)/P) with period P = 92160 = A377469(8) and shift S = 11741730 = A376237(9). - M. F. Hasler, Nov 17 2024
PROG
(PARI) my(L=vector(3913910, x, 3*x+1+x%2), m(n, k)=2^(n\/k*k)\(2^k-1)); for(i=3, 7, L=vecextract(L, 2^#L-m(#L, L[1])-1)); L255418=vecextract(L, m(#L, L[1]));
A255418(n, P=92160)=n--\P*11741730 + L255418[n%P+1] \\ M. F. Hasler, Nov 17 2024
(Python) # S can be decreased if only terms up to a smaller limit are needed.
def A255418(n, S=11741730, P=92160):
try: n-=1; return A255418.L[n]
except IndexError: return A255418.L[n%P] + n//P*S
except AttributeError: L = [x+5-x%2 for x in range(0, S, 3)]
while (k:=L[0]) < 23: L = [x for i, x in enumerate(L) if i%k]
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Feb 22 2015
STATUS
approved