A036689 -id:A036689 - cp's OEIS frontend

A174870 Odd indices m for which A174869(m) is <>1.

1, 9, 21, 25, 27, 33, 45, 57, 75, 77, 81, 85, 91, 93, 105, 115, 117, 121, 125, 133, 135, 141, 145, 147, 165, 169, 171, 175, 177, 187, 189, 201, 205, 213, 217, 221, 225, 231, 235, 243, 245, 247, 253, 261, 273, 275, 289, 297, 301, 315, 325, 333, 343, 345, 355, 357, 361, 363

Offset: 1

Vladimir Shevelev, Mar 31 2010

nonn

All but the first term in the sequence are composite numbers.

			The 9 refers to A174869(9) = 7. The 21 refers to A174869(21) = 3.

Cf. A174869, A006530, A103667, A023503, A023509, A174857, A020639 ,A002618, A036689.

More terms from R. J. Mathar, Aug 10 2010

A261465 a(n) = prime(n+1)^2 - prime(n).

Original entry on oeis.org

7, 22, 44, 114, 158, 276, 344, 510, 818, 932, 1338, 1644, 1808, 2166, 2762, 3428, 3662, 4428, 4974, 5258, 6168, 6810, 7838, 9320, 10104, 10508, 11346, 11774, 12660, 16016, 17034, 18638, 19184, 22062, 22652, 24498, 26412, 27726, 29762

Offset: 1

Altug Alkan, Aug 20 2015

			a(2) = 5^2 - 3 = 22.

Cf. A036689, A001223, A069482, A129701.

[NthPrime(n+1)^2-NthPrime(n): n in [1.. 70]]; // Vincenzo Librandi, Aug 20 2015

Table[Prime[n + 1]^2 - Prime[n], {n, 60}] (* Vincenzo Librandi, Aug 20 2015 *)

first(m)=vector(m,i,prime(i+1)^2 - prime(i)) \\ Anders Hellström, Aug 20 2015

a(n,p=prime(n)); nextprime(p+1)^2-p \\ Charles R Greathouse IV, Aug 22 2015

first(n)=my(v=primes(n+1)); vector(n,i,v[i+1]^2-v[i]) \\ Charles R Greathouse IV, Aug 22 2015

a(n) = A036689(n+1) + A001223(n). - Michel Marcus, Aug 21 2015 [Corrected by Georg Fischer, Dec 12 2022]

a(n) ~ n^2 log^2 n. - Charles R Greathouse IV, Aug 22 2015

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A174870 Odd indices m for which A174869(m) is <>1.

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A261465 a(n) = prime(n+1)^2 - prime(n).

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