A025471 Position of 5^n among the powers of primes (A000961).

1, 5, 15, 43, 137, 483, 1881, 7772, 33292, 146014, 650688, 2935909, 13377899, 61448617, 284148766, 1321470026, 6175996065, 28988110806, 136575209239, 645621236243, 3061130340023, 14552991533455, 69354804657255, 331251331834172, 1585299655420744, 7600886382041555, 36504944105963117

Offset

0,2

Links

Table of n, a(n) for n=0..26.

Formula

a(n) = A065515(5^n). - Michel Marcus, Mar 24 2013

Prog

(PARI) a(n) = n=5^n; 1+sum(k=1, logint(n, 2), primepi(sqrtnint(n, k))); \\ Daniel Suteu, Dec 15 2019

Crossrefs

Cf. A000351 (powers of 5), A000961, A065515.

Sequence in context: A032193 A178965 A005665 * A064453 A059251 A295179

Adjacent sequences: A025468 A025469 A025470 * A025472 A025473 A025474

Keyword

nonn

Author

Clark Kimberling

Extensions

a(13)-a(20) from Robert G. Wilson v, Dec 13 2019

a(21)-a(26) from Daniel Suteu, Dec 15 2019

Status

approved