A077576 a(1) = 1; for n > 1, a(n) = largest prime divisor of A062273(n).

1, 23, 19, 263, 823, 678901, 50993, 1279, 211, 150866941, 353594393, 757819, 9012345678901, 213408443, 11904282563, 435503, 21339439879, 7403356241, 13212859242013, 27961, 205126079, 5201061865265117273, 54843374833199, 1384232185401581113277, 12792129877

Offset

1,2

Links

Daniel Suteu, Table of n, a(n) for n = 1..131

Formula

a(n) = A006530(A062273(n)). - Michel Marcus, May 26 2022

Prog

(PARI) f(n) = sum(i=1, n, ((n*(n-1)/2+i) % 10)*10^(n-i)); \\ A062273
a(n) = my(x=f(n)); if (x==1, 1, vecmax(factor(x)[, 1])); \\ Michel Marcus, May 26 2022

Crossrefs

Cf. A006530, A062273.

Sequence in context: A105818 A085450 A077146 * A004512 A214342 A261308

Adjacent sequences: A077573 A077574 A077575 * A077577 A077578 A077579

Keyword

base,nonn

Author

Amarnath Murthy, Nov 11 2002

Extensions

More terms from Sascha Kurz, Jan 12 2003

a(24)-a(25) from Daniel Suteu, May 25 2022

Status

approved