A379079 Positions of 1's in the digit stream of A379651.

1, 3, 8, 9, 12, 13, 16, 17, 20, 21, 23, 25, 26, 33, 34, 35, 37, 41, 44, 46, 48, 49, 52, 54, 56, 59, 60, 62, 63, 69, 71, 72, 74, 76, 77, 79, 81, 82, 83, 84, 86, 88, 89, 90, 91, 92, 94, 96, 97, 98, 101, 102, 103, 104, 107, 108, 110, 116, 117, 119, 121, 122, 127, 128, 129, 131, 133, 134, 135, 136, 137, 140, 141, 144, 147, 148

Offset

1,2

Comments

The digits of A379651 are numbered starting at 1. Is there a recurrence?

Links

Thomas Scheuerle, Table of n, a(n) for n = 1..20000, (terms 1..5040 from N. J. A. Sloane).

Formula

Sum_{n >= 2} (4*5^(a(n)-2) - 1)/10^(a(n)-2) = 2. - Thomas Scheuerle, Jan 12 2025

Prog

(PARI) lista(max_n) = {my(v=[1, 3], m=3, s=19/10); while(#v < max_n, m++; while(s+(4*5^(m-2)-1)/10^(m-2) > 2, m++); v=concat(v, [m]); s=s+(4*5^(m-2)-1)/10^(m-2)); v} \\ Thomas Scheuerle, Jan 12 2025

Crossrefs

Cf. A379651.

Sequence in context: A225555 A047472 A304204 * A028960 A139491 A084387

Adjacent sequences: A379076 A379077 A379078 * A379080 A379081 A379082

Keyword

nonn,base,changed

Author

N. J. A. Sloane, Jan 11 2025

Status

approved