A049926 a(n) = a(1) + a(2) + ... + a(n-1) - a(m) for n >= 4, where m = n - 1 - 2^p and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1 and a(2) = a(3) = 3.

1, 3, 3, 6, 10, 22, 42, 84, 165, 335, 668, 1336, 2669, 5334, 10656, 21292, 42542, 85167, 170332, 340664, 681325, 1362646, 2725280, 5450540, 10901038, 21801995, 43603820, 87207307, 174413946, 348826559, 697650453, 1395295584

Offset

1,2

Links

Table of n, a(n) for n=1..32.

Prog

(PARI) lista(nn) = { my(va = vector(nn)); va[1] = 1; va[2] = 3; va[3] = 3; my(sa = vecsum(va)); for (n=4, nn, va[n] = sa - va[n - 1 - 2^ceil(-1 + log(n-1)/log(2))]; sa += va[n]; ); va; } \\ Petros Hadjicostas, Apr 26 2020

Crossrefs

Sequence in context: A304265 A049871 A049924 * A298954 A169944 A110952

Adjacent sequences: A049923 A049924 A049925 * A049927 A049928 A049929

Keyword

nonn

Author

Clark Kimberling

Extensions

Name edited by Petros Hadjicostas, Apr 26 2020

Status

approved